KR20070121671A - Optical compensation film, polarizing plate and liquid crystal display - Google Patents

Abstract

An optical compensation film is provided and has a cellulose acylate film coated with an optically anisotropic layer containing a liquid crystalline compound, cellulose having a glucose unit, a hydroxyl group of the glucose unit being substituted with an acyl group having at least two carbon atoms. The cellulose acylate film satisfies relationships specified in the specification.

Description

Optical compensation film, polarizer, and liquid crystal display {OPTICAL COMPENSATION FILM, POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY}

Field of technology

The present invention relates to an optical compensation film and a polarizing plate and a liquid crystal display using the optical compensation film, respectively.

Background

Liquid crystal displays are widely used for many applications, including personal computers, portable device monitors, and televisions, for example, because of their various advantages, such as low voltage and low power consumption in operation, and the possibility of high reduction in size and profile. Is used. The liquid crystal display has been proposed in various modes according to the arrangement state of the liquid crystal molecules in the liquid crystal cell, but conventionally the liquid crystal molecules in the alignment state twisted by about 90 degrees from the lower substrate to the upper substrate of the liquid crystal cell TN The mode is dominant.

Generally, a liquid crystal display is composed of a liquid crystal cell, an optical compensation film, and a polarizer. An optical compensation film is used to dissipate image coloring or to enlarge the viewing angle, and a birefringent stretched film or a transparent film coated with liquid crystal is used as the optical compensation film. For example, in Japanese Patent No. 2587398, an optical compensation film formed by coating a discotic liquid crystal on a triacetylcellulose film, leaving the liquid crystal in an oriented state and fixing the oriented state, is applied to a liquid crystal cell of TN mode. Techniques for expanding the viewing angle are disclosed. Liquid crystal displays for televisions with large screens and viewed from various angles have strict requirements for viewing angle dependence, but the above-described technique cannot satisfy this requirement. Under these circumstances, liquid crystal displays different from TN modes such as In-Plane Switching (IPS) mode, 0ptically Compensatory Bend (0CB) mode, Vertically Aligned (VA) mode, and the like have been studied. In particular, the IPS mode is attracting attention as a liquid crystal display device for TV because the change in the gray scale characteristic due to the viewing angle is small.

The cellulose acylate film has a high optical anisotropy (low retardation value) compared with other polymer films. Therefore, it is common to use a cellulose acetate film for the use which requires optical anisotropy like a polarizing plate.

In contrast, optical anisotropy (high retardation value) is required for the optical compensation film (retardation film) used in the liquid crystal display. In particular, when the cellulose acylate film is applied to an IPS mode liquid crystal display, a Re value in the range of 20 nm to 150 nm and a Re / Rth in the range of 1.5 to 7 are required.

Conventionally, in the technical field of optical materials, synthetic polymer films are used when optical anisotropy (high retardation value) is required for the polymer film, but cellulose is required when optical isotropy (low retardation value) is required for the polymer film. It was a common rule to use acetate films.

European Patent Publication No. 911656 discloses a cellulose acetate film having a high retardation value that can be used even in applications where optical anisotropy is required, in contrast to conventional rules up to now. In order to achieve high retardation value when using cellulose acetate, in this invention, the compound which has at least 2 aromatic ring, especially the compound which has 1, 3, 5-triazine ring is added, and an extending | stretching process is performed.

In general, cellulose acetate is a difficult material to be stretched, and it is known that it is difficult to increase the birefringence rate, but it is possible to increase the birefringence rate by orienting additional molecules at the same time by the stretching treatment, thereby resulting in a high retardation value. It is mentioned in the patent literature that this is achieved.

Since such a film can serve as a protective film of a polarizing plate, there is an advantage that a thin liquid crystal display device can be provided at a low cost.

Japanese Laid-Open Patent Publication No. 2002-71957 has a 2 to 4C acyl group as a substituent, and the substitution degree of the acetyl group is A, and the substitution degree of the propionyl group or the butyryl group is B, 2.0 ≦ A + B ≦ An optical film containing a cellulose ester which satisfies both 3.0 and A <2.4, wherein the refractive index measured by light of 590 nm in the slow axis direction is called Nx and the refractive index measured by light of 590 nm in the fast axis direction When Ny is referred to as Ny, an optical film that satisfies the relationship of 0.0005 ≦ Nx−Ny ≦ 0.0050 is disclosed.

In the IPS mode, as one of the methods of improving the viewing angle in the state of a hue or black state display device, disposing an optical compensation material having birefringence property between the liquid crystal layer and the polarizing plate has been studied. For example, a field of view from an oblique direction can be obtained by disposing a birefringent medium between the substrate and the polarizing plate, each of which has a function of compensating for the increase and decrease of the retardation of the liquid crystal layer in an inclined state, and the optical axis crosses at right angles. When possible, it is disclosed that the color can be improved in the white display state or the halftone display state (see Japanese Patent Laid-Open No. 9-80424). In addition, a method using an optical compensation film having a negative intrinsic birefringence and containing a styrene polymer or a discotic liquid crystal compound (see Japanese Patent Application Laid-Open Nos. 10-54982, 11-202323, and 9-292522), Method using an optical compensation film which is a combination of a film having a positive birefringence and an in-plane optical axis of the film, and a film having a positive birefringence and an optical axis in a direction perpendicular to the film (JP-A-11-133408), A method using a biaxial optical compensation film having a retardation of one wavelength (see Japanese Patent Application Laid-Open No. 11-305217), using a film having a negative retardation as a protective film of a polarizing plate, and using a positive retardation on the surface of the film A method of providing an optical compensation layer having a structure (see Japanese Patent Laid-Open No. Hei 10-307291) has been proposed.

In Japanese Patent Application Laid-Open No. 9-211444 and Japanese Patent Laid-Open No. 11-316378, an optical compensation film having a layer made of a liquid crystal compound is provided to a polarizing plate used for an OCB mode liquid crystal display, whereby Viewing angle is achieved.

The method disclosed in the above-mentioned document has the effect of allowing a thin liquid crystal display to be manufactured at low cost. However, in recent years, the use of liquid crystal displays in various environments has increased, and the optical compensation performance of the cellulose ester film using the previous technology under such circumstances is problematic. More specifically, the cellulose ester film using the above technique is affected by changes in the environment, inter alia, humidity, in particular when attaching them on the liquid crystal cell, thereby retardation value and Rth. There was a problem that the optical compensation performance is changed due to the change in the retardation value. Therefore, a solution to this problem is required.

Disclosure of the Invention

An object of embodiments of the present invention, which is not intended to be limiting but exemplary, is to use a cellulose acylate film that exhibits excellent in-plane retardation and thickness direction retardation characteristics, and an optical compensation film in which retardation changes due to ambient humidity are reduced. Another object of an embodiment of the present invention, which is provided by way of example and not by way of limitation, is to provide a polarizing plate using such an optical compensation film.

An additional object of the illustrative, non-limiting embodiments of the present invention is to provide a liquid crystal display with reduced variation in viewing angle characteristics.

These objects are obtained by the following embodiments of the present invention.

(1-1) A compensation film having a cellulose acylate film coated with an optically anisotropic layer containing a rod-like liquid crystalline compound, wherein the cellulose acylate film is substituted with cellulose having a glucose unit and an acyl group having two or more carbon atoms It has a hydroxyl group of glucose units, and a cellulose acylate film satisfies the relationship (I) and (II).

(I): 2.0≤DS2 + DS3 + DS6≤3.0

(II): DS6 / (DS2 + DS3 + DS6) ≥0.315

Here, DS2 means the degree of substitution of the hydroxyl group at the 2-position of the glucose unit to the acyl group, DS3 means the degree of substitution at the 3-position of the glucose unit with the acyl group, and DS6 means 6 of the glucose unit. The degree of substitution of the hydroxyl group at the-position with the acyl group.

(1-2) The optical compensation film described in (1-1), wherein the cellulose acylate film has a Re (550) value of 20 nm to 150 nm and an Rth (550) / Re (550) ratio of 1.5 to 7, and 0 and an optically anisotropic layer containing a rod-like liquid crystalline compound having a Re (550) value of nm to 10 nm and an Rth (550) value of -80 nm to -400 nm.

[In (1-2), Re (λ) is in-plane retardation expressed in unit nm at wavelength λnm, and Rth (λ) is thickness direction retardation expressed in unit of nm at wavelength λnm.]

(1-3) The optical compensation film described in (1-1) or (1-2), wherein the retardation value Re (550) of the cellulose acylate film under the conditions of 25 ° C and 10% RH and 25 ° C and 80% The difference between the retardation value Re (550) of the cellulose acylate film under the conditions of RH, ㅿ Re (Re10% RH-Re80% RH) becomes 12 nm or less, and the cellulose acylate under the conditions of 25 ° C and 10% RH. The difference between the Rth (550) of the film and the retardation value Rth (550) of the cellulose acylate film under the conditions of 25 ° C and 80% RH, the difference between ㅿ Rth (Rth10% RH-Rth80% RH) is 32 nm or less do.

[In (1-3), Re (λ) is in-plane retardation expressed in unit nm at wavelength (λ nm), and Rth (λ) is thickness direction retardation expressed in nm unit at wavelength (λ nm). ]

(1-4) The polarizing plate which has the optical compensation film and polarizer in any one of (1-1)-(1-3).

(1-5) The liquid crystal display device which has the liquid crystal cell and optical compensation film in any one of (1-1)-(1-3), or the polarizing plate as described in (1-4).

(1-6) The liquid crystal display device according to (1-5), in which an IPS mode is used.

Moreover, the following mode is also preferable in this invention.

(1-7) The optical compensation film in any one of (1-1)-(1-3) whose acyl group of a cellulose acylate film is an acetyl group.

(1-8) The cellulose acylate film is an optical compensation film according to any one of (1-1) to (1-3), which contains at least one retardation expression agent containing a rod-like or discotic compound.

(1-9) The cellulose acylate film is an optical compensation film according to any one of (1-1) to (1-3), which contains at least one additive selected from a plasticizer, an ultraviolet absorber, or a parting accelerator.

(1-10) The cellulose acylate film is an optical compensation film according to any one of (1-1) to (1-3), which has a thickness of 40 µm to 180 µm.

(1-11) The optical compensation film in any one of (1-1)-(1-3) whose content of the additive added to a cellulose acylate film is 10%-30% of the mass of a cellulose acylate film.

(1-12) The cellulose acylate film has an equilibrium moisture content of 3.4% or less at a temperature of 25 ° C. and a humidity of 80% RH, and the optical compensation film according to any one of (1-1) to (1-3).

(1-13) in 60 ℃, 95% RH, and a moisture permeability of the moisture 24 hr under the condition of the cellulose acylate film (film thickness calculated as 80㎛) 400g / m ² 24 hr to about 2,300g / m ² 24 hr ( The optical compensation film in any one of 1-1)-(1-3).

(1-14) The cellulose acylate film is any one of (1-1) to (1-3) having a mass change of 0% to 5% when placed under conditions of 40 ° C. and 90% RH for 48 hours. Described Optical Compensation Film

(1-15) The change in the dimensions of the cellulose acylate film when placed for 24 hours under the conditions of 60 ° C. and 95% RH and the change in the dimensions of the cellulose acylate film when placed for 24 hours under the conditions of 90 ° C. and 5% RH Both optical compensation films as described in any one of (1-1)-(1-3) which exist in the range of 0%-5%.

(1-16) The cellulose acylate film has an optical compensation film according to any one of (1-1) to (1-3), which has a glass transition temperature Tg of 30 ° C to 130 ° C.

(1-17) The cellulose acylate film is an optical compensation film according to any one of (1-1) to (1-3), which has an elastic modulus of 1,500 MPa to 5,000 MPa.

(1-18) The cellulose acylate film has an optical compensation film according to any one of (1-1) to (1-3), which has a photoelastic coefficient of 50 × 10 ⁻¹³ cm ² / dyne or less.

(1-19) The cellulose acylate film is an optical compensation film according to any one of (1-1) to (1-3), which has a haze of 0.01% to 2%.

(1-20) The cellulose acylate film has an average diameter of secondary particles, the optical compensation film according to any one of (1-1) to (1-3) having fine particles of silicon dioxide in the range of 0.2 µm to 1.5 µm. .

(1-21) Single plate transmittance (TT) and parallel transmittance (PT) satisfying the following formulas (a), (b), (c) or (d) when measured under the condition of 25 ° C and 60% RH, respectively. ), Orthogonal transmittance (CT), or the polarizing plate according to (1-4) further having one or more factors selected from polarization degree (P).

(a) 40.0≤TT≤45.0

(b) 30.0≤PT≤40.0

(c) CT≤2.0

(d) 95.0≤P

(1-22) When the orthogonal transmittance measured at wavelength (λ nm) is expressed by CT (λ), one or more of the following formulas (e), (f), and (g) are further satisfied in consideration of the orthogonal transmittance of the plate The polarizing plate as described in (1-4).

(e) CT (380) ≤ 2.0

(f) CT 410 ≤ 0.1

(g) CT (700) ≤0.5

(1-23) A change in orthogonal transmittance (ㅿ CT) or change in polarization degree that satisfies the following formula (j) or (k) when the plate is allowed to withstand 500 hours under the condition of 60 ° C and 95% RH ( The polarizing plate as described in (1-4) which further has at least any one of VIIP).

(j) -6.0≤ ㅿ CT≤6.0

(k) -10.0≤ ㅿ P≤0.0

(Here, the variation is defined as the value obtained by subtracting the pre-test measurement from the post-test measurement.)

(1-24) The polarizing plate according to (1-4), which further provides at least one layer selected from a hard coating layer, an antiglare layer, and an antireflection layer on the surface of the protective film disposed to face the liquid crystal cell.

(1-25) The polarizing plate as described in (1-4) packaged in the moisture proof bag which has the internal humidity adjusted to the range of 43% RH-65% RH at 25 degreeC.

(1-26) The polarizing plate as described in (1-4) packaged in the moisture proof bag which has the internal humidity adjusted so that it may differ by 15% RH or less from ambient humidity when a polarizing plate is laminated on a liquid crystal panel.

The above object is also achieved by the following embodiments of the present invention.

(2-1) A compensation film having a cellulose acylate film coated with an optically anisotropic layer containing a liquid crystalline compound, wherein the cellulose acylate film is a cellulose unit having glucose units and a glucose unit substituted with an acyl group having two or more carbon atoms It has a hydroxyl group of, and a cellulose acylate film satisfies the relationship (I) and (II).

(I): 2.0≤DS2 + DS3 + DS6≤3.0

(II): DS6 / (DS2 + DS3 + DS6) ≥0.315

Here, DS2 means the degree of substitution of the hydroxyl group at the 2-position of the glucose unit to the acyl group, DS3 means the degree of substitution at the 3-position of the glucose unit with the acyl group, and DS6 means 6 of the glucose unit. The degree of substitution of the hydroxyl group at the-position with the acyl group.

(2-2) The optical compensation film as described in (2-1) in which a cellulose acylate film contains one or more retardation expression agents containing rod shape or a discotic compound.

(2-3) The difference between the retardation value Re (550) of the cellulose acylate film under the conditions of 25 ° C and 10% RH and the retardation value Re (550) of the cellulose acylate film under the conditions of 25 ° C and 80% RH. ㅿ Re (Re10% RH-Re80% RH) is 12 nm or less, and the retardation value Rth (550) of the cellulose acylate film under 25 ° C and 10% RH conditions and cellulose acyl under the conditions of 25 ° C and 80% RH. The optical compensation film as described in (2-1) or (2-2) in which the difference between retardation value Rth (550) of a late film and -Rth (Rth10% RH-Rth80% RH) becomes 32 nm or less.

[In (2-3), Re (λ) is in-plane retardation expressed in unit nm at wavelength (λ nm), and Rth (λ) is thickness direction retardation expressed in unit nm at wavelength (λ nm). ]

(2-4) The liquid crystal compound is a polarizing plate in any one of (2-1)-(2-3) which is a discotic liquid crystal compound.

(2-5) The polarizing plate and polarizer which have an optical compensation film in any one of (2-1)-(2-4).

(2-6) The liquid crystal display device which has a liquid crystal cell in any one of (2-1)-(2-4), and an optical compensation film, or the polarizing plate as described in (2-5).

(2-7) The liquid crystal display device according to (2-6), in which the OCB mode is used.

In the present invention, the following modes are also preferred.

(2-8) The optical compensation film in any one of (2-1)-(2-4) whose acyl group of a cellulose acylate film is an acetyl group.

(2-9) The cellulose acylate film is an optical compensation film according to any one of (2-1) to (2-4), which contains at least one additive selected from a plasticizer, an ultraviolet absorber, or a parting accelerator.

(2-10) The cellulose acylate film is an optical compensation film according to any one of (2-1) to (2-4), which has a thickness of 40 µm to 180 µm.

(2-11) The optical compensation film in any one of (2-1)-(2-4) whose content of the additive added to a cellulose acylate film is 10%-30% of the mass of a cellulose acylate film.

(2-12) The cellulose acylate film has an optical compensation film according to any one of (2-1) to (2-4), having an equilibrium moisture content of 3.4% or less at a temperature of 25 ° C and a humidity of 80% RH.

(2-13) in 60 ℃, 95% RH, and a moisture permeability of the moisture 24 hr under the condition of the cellulose acylate film (film thickness calculated as 80㎛) 400g / m ² 24 hr to about 2,300g / m ² 24 hr ( The optical compensation film in any one of 2-1)-(2-4).

(2-14) Any of (2-1) to (2-4) having a mass change of 0 to 5% when the cellulose acylate film is allowed to withstand for 48 hours at 80 ° C. and 90% RH. Optical compensation film described in one

(2-15) Change in the dimensions of the cellulose acylate film when allowed to withstand 24 hours under conditions of 60 ° C. and 95% RH and cellulose acyl when allowed to withstand 24 hours under conditions of 90 ° C. and 5% RH. The dimensional change of a rate film is an optical compensation film as described in any one of (2-1)-(2-4) which are both in the range of 0%-5%.

(2-16) The cellulose acylate film has an optical compensation film according to any one of (2-1) to (2-4), which has a glass transition temperature (Tg) of 80 ° C to 180 ° C.

(2-17) The cellulose acylate film is an optical compensation film according to any one of (2-1) to (2-4), which has an elastic modulus of 1,500 MPa to 5,000 MPa.

(2-18) The cellulose acylate film has an optical compensation film according to any one of (2-1) to (2-4), which has a photoelastic coefficient of 50 × 10 ⁻¹³ cm ² / dyne or less.

(2-19) The cellulose acylate film is an optical compensation film according to any one of (2-1) to (2-4), which has a haze of 0.01% to 2%.

(2-20) The cellulose acylate film has an optical compensation film according to any one of (2-1) to (2-4), wherein the secondary average particle size has fine particles of silicon dioxide in a range of 0.2 µm to 1.5 µm.

The liquid crystal compound (2-21) is an optical compensation film in any one of (2-1)-(2-16) which is a discotic liquid crystalline compound.

(2-22) Single plate transmittance (TT) and parallel transmittance (PT) satisfying the following formulas (a), (b), (c), or (d) when measured under the condition of 25 ° C and 60% RH. ), Orthogonal transmittance (CT), or the polarizing plate according to (2-5) which further has at least one factor selected from the degree of polarization (P).

(a) 40.0≤TT≤45.0

(b) 30.0≤PT≤40.0

(c) CT≤2.0

(d) 95.0≤P

(2-23) When the orthogonal transmittance measured at the wavelength (λ nm) is represented by CT (λ), one or more of the following formulas (e), (f), and (g) are further satisfied in consideration of the orthogonal transmittance of the plate: The polarizing plate as described in (2-5).

(e) CT (380) ≤ 2.0

(f) CT 410 ≤ 0.1

(g) CT (700) ≤0.5

(2-24) Change in orthogonal transmittance (ㅿ CT) or change in polarization degree when the plate is allowed to withstand 500 hours under the conditions of 60 ° C. and 95% RH, satisfying the following formula (j) or (k) ( The polarizing plate as described in (2-5) which further has at least any one of VIIP).

(j) -6.0≤ ㅿ CT≤6.0

(k) -10.0≤ ㅿ P≤0.0

(Here, the variation is defined as the value obtained by subtracting the pre-test measurement from the post-test measurement.)

(2-25) The polarizing plate according to (2-5), which further provides one or more layers selected from a hard coating layer, an antiglare layer, and an antireflection layer on the surface of the protective film disposed to face the liquid crystal cell.

(2-26) The polarizing plate as described in (2-5) packaged in the moisture proof bag which has internal humidity adjusted to the range of 43% RH-65% RH at 25 degreeC.

(2-27) The polarizing plate as described in (2-5) packaged with the moisture proof bag which has the internal humidity adjusted so that it may differ with ambient humidity and 15% RH or less when a polarizing plate is laminated | stacked on a liquid crystal panel.

According to the present invention, there is provided an optical compensation film using a cellulose acylate film having excellent in-plane and thickness direction retardation characteristics and having reduced retardation change with ambient humidity, and further providing a polarizing plate using the optical compensation film. It is possible.

In addition, the present invention can provide a liquid crystal display device having reduced viewing angle characteristic change.

Brief description of the drawings

1 is a schematic diagram showing an example of one pixel area in a liquid crystal display according to the present invention.

2 is a schematic diagram showing an example of a liquid crystal display according to the present invention.

3 is a schematic diagram showing another example of a liquid crystal display according to the present invention.

Detailed description of the invention

Exemplary embodiments of the invention are described in detail below.

(Cellulose acylate)

Preferably, the cellulose acylate used in the present invention will be described in detail. Each glucose unit constituting cellulose through a β-1,4 bond does not have a hydroxyl group at its 2-, 3-, and 6-positions. Cellulose acylate is a polymer obtained by esterifying some or all of these hydroxyl groups with an acyl group. Acyl substitution degrees (DS2, DS3, and DS6) mean esterification rates for hydroxyl groups at 2-, 3-, and 6-positions respectively (for 100 esterification, the degree of substitution is 1).

As for total acyl substitution degree, or DS2 + DS3 + DS6, 2.00-3.00 are preferable, 2.22-2.90 are more preferable, and 2.40-2.82 are still more preferable. In addition, DS6 / (DS2 + DS3 + DS6) is preferably 0.315 or more, more preferably 0.322 or more, and particularly preferably 0.324 to 0.340. Here, DS2 means substitution degree of 2-position hydroxyl group of glucose unit (hereinafter, called "2-position acyl substitution degree"), DS3 means substitution degree of 3-position hydroxyl group of glucose unit (hereinafter, "3- DS6 means the degree of substitution of the 6-position hydroxyl group of the glucose unit (hereinafter referred to as "6-position acyl substitution degree").

The acyl group used for the cellulose acylate according to the present invention may be composed of only one kind of acyl group or two or more kinds of acyl groups. When two or more kinds of acyl groups are used, one of these is preferably an acetyl group. The total substitution degree of the acetyl group for the 2-position, 3-position, and 6-position hydroxyl groups is indicated as DSA, and the acyl groups other than the acetyl group for the 2-position, 3-position, and 6-position hydroxyl groups Total substitution degree is represented by DSB, and the value of DSA + DSB is preferably 2.2 to 2.86, particularly preferably 2.40 to 2.80. In addition, the value of DSB is 1.50 or more, and 1.7 or more is especially preferable. Moreover, at least 28% of the DSB values are degrees of substitution at the 6-position hydroxyl groups. Moreover, the substitution degree ratio in the 6-position receiver of the DSB value is preferably at least 30%, more preferably at least 31%, particularly preferably at least 32%. Alternatively, it is possible to use cellulose acylate films having a DSA + DSB value at the 6-position of at least 0.75, preferably at least 0.80, particularly preferably at least 0.85. These cellulose acylate films make it possible to prepare good solutions with good solubility, especially when organic solvents free of chlorine are used. In addition, by using these films, a solution having a low viscosity and high filtration efficiency can be prepared.

The acyl group in the cellulose acylate according to the present invention having two or more carbon atoms per acyl group may be an aliphatic group or an aromatic group and is not particularly limited. The cellulose acylate may be an alkyl carbonyl or alkenyl carbonyl ester of cellulose or an arylcarbonyl ester or aryl- and alkcarbonyl ester of cellulose, which may each further have a substituent. Suitable examples of such silyl groups are acetyl, propionyl, butanoyl, pentanoyl, hexanoyl, octanoyl, dicanoyl, dodecanoyl, tridicanoyl, tetradicanoyl, hexadicanoyl, octadicanoyl, iso-butayl Noyl, t-butanoyl, cyclohexanecarbonyl, oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl. Of these groups, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl are preferred among others, and acetyl, propionyl, And butanoyl are particularly preferred.

(Synthesis method of cellulose acylate)

The basic principle of the method of synthesizing cellulose acylate is described in Wood Chemistry, Migita et al., Pages 180-190 (Kyoritsu Shuppan Co., Ltd., 1968). Typical synthetic methods are liquid esterification with carboxylic anhydride, acetic acid, and sulfuric acid catalysts. In particular, complete cellulose acylate is synthesized by pretreatment of a cellulose raw material such as cotton linter or wood pulp with an appropriate amount of acetic acid and then placed in a precooled carboxylic acid mixture to effect esterification (2-, The sum of degrees of substitution at the 3-, and 6-positions is about 3.). The above mentioned carboxylation mixtures generally contain acetic acid as a solvent, carboxylic anhydride as an esterifying agent, and sulfuric acid as a catalyst. Typically, carboxylic anhydrides are used in stoichiometry that exceeds the sum of the cellulose reacting with it and the moisture present in the system. After completion of the acylation reaction, neutralizing agents (e.g., carbonates of calcium, magnesium, iron, aluminum, or zinc) for the hydrolysis of excess carboxylic anhydride remaining in the system and for the neutralization of some of the esterification catalysts, An aqueous solution of acetate, or oxide) is added. The complete cellulose acylate thus obtained is then maintained at 50 ° C. to 90 ° C. in the presence of a small amount of acetylation reaction catalyst (generally, sulfuric acid remaining) to saponify and mature, thereby obtaining complete cellulose acylate. It is changed to cellulose acylate which has acyl substitution degree and polymerization degree. At the point of obtaining the desired cellulose acylate, the catalyst remaining in the system is completely neutralized with a neutralizing agent as described above, or the cellulose acylate solution is added to water or diluted conversion without neutralizing (or cellulose acylate The solution is poured with water or diluted sulfuric acid) to separate the cellulose acylate, and the cellulose acylate is obtained by washing and stabilizing treatment.

In the cellulose acylate film of the present invention, it is preferred that the polymer component constitute a film substantially comprising the cellulose acylate as defined above. "Substantially" means 55 mass% or more (preferably 70 mass% or more, more preferably 80 mass% or more) of a polymer component. As a raw material for producing the film, it is preferable to use cellulose acylate particles. It is preferred that at least 90 mass% of the particles used have a particle size of 0.5 mm to 5 mm. Moreover, it is preferable that at least 50 mass% of the particles used have a particle size of 1 mm to 4 mm. It is preferable that the cellulose acylate particles have a shape as close to a sphere as possible.

The viscosity average degree of polymerization of the cellulose acylate used preferably in the present invention is 200 to 700, preferably 250 to 550, more preferably 250 to 400, particularly preferably 250 to 350. The average degree of polymerization can be measured by intrinsic viscosity methods such as Uda et al. (Kazuo Uda and Hideo Saito, Seni-Gakkai Shi (The Journal of the Society of Fiber Science and Technology, Japan) 18 (1), 105-120, 1962). have. It is described in detail in Unexamined-Japanese-Patent No. 9-95538.

When the low molecular weight component is removed from the cellulose acylate, its average molecular weight (polymerization degree) is high. However, the viscosity is lower than that of ordinary cellulose acylate, and the removal of the low molecular weight component is useful. Cellulose acylate containing a low molecular weight component in a small amount can be obtained by removing the low molecular weight component from the cellulose acylate synthesized by the general method. Removal of the low molecular weight component can be effected by washing the cellulose acylate with a suitable organic solvent. When cellulose acylate containing a low molecular weight component in a small amount is produced, the amount of sulfuric acid catalyst in the acylation reaction is preferably adjusted to 0.5 to 25 parts by weight based on 100 parts by weight of cellulose. Even at the point of molecular weight distribution (uniform molecular weight distribution), preferred cellulose acylate can be synthesized by adjusting the amount of sulfuric acid catalyst within the above-mentioned range. When used in the production of the cellulose acylate film of the present invention, the cellulose acylate has a moisture content of 2% by mass, more preferably 1% by mass, and particularly preferably 0.7% by mass. Typically, cellulose acylate containing water, its water content is known to be 2.5% by mass to 5% by mass. In order to adjust the cellulose acylate to this water content in the present invention, drying is required, and the method for this is not particularly limited as long as a desired water content is obtained.

Raw cotton and synthetic methods of these cellulose acylates used in the present invention are described in detail in JIII Journal of Technical Disclosure No. 2001-1745, pages 7 to 12 (published May 15, 2001, Japan Institute of Invention and Innovation).

(additive)

In the cellulose acylate solution of the present invention, various additives (for example, a plasticizer, a sunscreen, a deterioration inhibitor, a retardation (optical anisotropic) expression agent, a fine particle, a mold release agent, and an infrared absorber) according to the use in each preparation step. May be added and may be either a solid product or an oily substance. That is, it is not specifically limited in the melting point or boiling point. For example, ultraviolet absorbents having a melting point below 20 ° C. and a melting point above 20 ° C. may be mixed with each other, or a plasticizer may be similarly mixed, for example, JP 2001-151901 A. It is described in. Examples of mold release agents include ethyl esters of citric acid. Moreover, infrared absorbing dyes are described, for example, in Japanese Patent Laid-Open No. 2001-194522. The addition time may be added at any time of the dope preparation process, and the step of adding an additive may be added to the last step of the dope preparation process. Moreover, the amount of each material added is not particularly limited as long as it shows its function. When the cellulose acylate film is formed of multiple layers, the type and amount of additives added to each layer may be different. This is described, for example, in Japanese Patent Laid-Open No. 2001-151902, which has been known in the past. It is preferable to adjust the elasticity modulus measured by the tensile tester to the glass transition temperature (Tg) of a cellulose acylate film at 70 degreeC-145 degreeC by the kind of these additives, and the addition amount thereof, and to 1500-3000 Mpa. Furthermore, JIII Journal of Technical Disclosure No. 2001-1745, page 16, published May 15, 2001, Japan Institute of Invention and Innovation.

(Plasticizer)

It is preferable that the existing film contains a plasticizer. The compounds usable as plasticizers in existing films are not particularly limited, but, for example, in phosphate esters, triphenyl phosphate, tricresyl phosphate, cresyldiphenyl phosphate, octyldiphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, And in tributyl phosphate, phthalic acid ester, diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, and di-2-ethylhexyl phthalate, and glycol esters in triacetin, tributy Lean, butylphthalylbutyl glycolate, ethylphthalylethyl glycolate, methylphthalylethyl glycolate, and butylphthalylbutyl glycolate, more preferably hydrophobic than cellulose acylate. These plasticizers may be used alone or in combination of two or more if necessary.

(Retardation expression agent)

In the present invention, in order to express the retardation value, it is understood that a compound having at least two aromatic rings can be used as the retardation expression agent. The amount of the retardation expression agent is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, still more preferably 0.2 to 5 parts by mass, even more preferably 0.5 to 2 parts by mass with respect to 100 parts by mass of the polymer. desirable. Two or more retardation expression agents may be used in combination.

It is preferred that the retardation expression agent have a maximum absorption in the wavelength region of 250 nm to 400 nm and have substantially no absorption in the visible region.

The term "aromatic ring" as used herein is intended to include aromatic hydrocarbon rings as well as aromatic heterocyclic rings.

The aromatic hydrocarbon ring is particularly preferably a six-membered ring (ie, a benzene ring).

The aromatic heterocyclic ring is generally an unsaturated heterocyclic ring, and the aromatic heterocyclic ring is preferably a 5-membered ring, a 6-membered ring, or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring. Aromatic heterocyclic rings each generally have the most double bonds. The hetero atoms may preferably contain nitrogen, oxygen, and sulfur atoms, inter alia nitrogen atoms. Examples of aromatic heterocyclic rings include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring , Pyran ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, and 1,3,5-triazine ring.

Suitable aromatic rings include benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring, and 1, 3,5-tri It is a azine ring. Among these rings, the 1,3,5-triazine ring is particularly preferable. More specifically, the compound disclosed in Japanese Patent Laid-Open No. 2001-166144 can be advantageously used.

2-20 are preferable, as for the number of the aromatic rings which have a retardation expression agent, 2-12 are more preferable, 2-8 are more preferable, and 2-6 are especially preferable.

The bond relationship between two aromatic rings can be classified as (a) when the ring forms a condensed ring, (b) when the ring is directly bonded as a single bond, or (c) when the ring is bonded via a linking group (two Spiro bonds cannot be formed because the two rings are aromatic rings). The coupling relationship of the present specification may be any one of (a) to (c).

In the case of (a), examples of the condensed ring (formed from two or more aromatic rings) include indene ring, naphthalene ring, azulene ring, fluorene ring, phenanthrene ring, anthracene ring, acenaphthylene ring, biphenylene ring, Naphxene ring, pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indolizine ring, benzoxazole ring, benzothiazole ring, benzoimidazole ring, benzotriazole ring, purine ring, Indazole ring, chromen ring, quinoline ring, isoquinoline ring, quinolysin ring, quinazole ring, cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, axridine ring , Phenanthridine ring, xanthene ring, phenazine ring, phenothiazine ring, phenoxtin ring, phenoxazine ring, and thianthrene ring. Among these rings, naphthalene ring, azulene ring, indole ring, benzoxazole ring, benzotaazole ring, benzoimidazole ring, benzotriazole ring, and quinoline ring are preferred over the others.

In case (b), the single bond is preferably a carbon-carbon bond between two aromatic rings. Two aromatic rings may be bonded by two or more single bonds to form an aliphatic ring or a non-aromatic heterocyclic ring between the two aromatic rings.

In case (c), the linking group is also preferably bonded to the carbon atoms of the two aromatic rings. The linking group is preferably an alkylene group, an alkenylene group, an alkylylene group, -CO-, -O-, -NH-, -S-, or a combination of two or more thereof. Examples of linking groups formed by combining any two or more of those mentioned above are shown below. In addition, each connector mentioned below may be inverted left and right.

c1: -CO-0

c2: -CO-NH

c3: -alkylene-O-

c4: -NH-CO-NH-

c5: -NH-CO-O-

c6: -O-CO-O-

c7: -O-alkylene-O-

c8: -C0-alkenylene-

c9: -CO-alkenylene-NH-

c10: -CO-alkenylene-O-

c11: -alkenylene-CO-0-alkylene-0-CO-alkylene-

c12: -O-alkylene-CO-O-alkylene-O-CO-alkylene-O-

c13: -O-CO-alkylene-CO-O-

c14: -NH-CO-alkenylene-

c15: -O-CO-alkenylene-

Aromatic rings and linking groups may have a substituent.

Examples of such substitution include halogen atom (F, Cl, Br, I), hydroxyl group, carboxyl group, cyano group, amino group, nitro group, sulfo group, carbamoyl group, sulfamoyl group, ureido group, alkyl group, alkenyl group, Alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amido group, aliphatic sulfonamido group, aliphatic substituted amino group, aliphatic substituted carbamoyl group , Aliphatic substituted sulfamoyl group, aliphatic substituted ureido group, and non-aromatic heterocyclic group.

As for carbon number of an alkyl group, 1-8 are preferable. Straight alkyl groups are preferred cycloalkyl groups, and linear alkyl groups are particularly preferred. These alkyl groups may further have substituents (such as hydroxyl, carboxyl, alkoxy, and alkyl substituted amino groups). Examples of such alkyl groups (including substituted alkyl groups) include methyl, ethyl, n-butyl, n-hexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl, and 2-diethylaminoethyl do.

As for carbon number of an alkenyl group, 2-8 are preferable. Straight alkenyl groups are preferred cycloalkenyl groups, and linear alkenyl groups are particularly preferred. These alkenyl groups may further have a substituent. Examples of such alkenyl groups include vinyl, aryl, and 1-hexenyl.

As for carbon number of an alkenyl group, 2-8 are preferable. A straight alkynyl group is preferable to a cyclo alkynyl group, and a linear alkynyl group is especially preferable. These alkynyl groups may further have a substituent. Examples of such alkynyl groups include ethynyl, 1-butynyl, and 1-hexynyl.

As for the number of carbon atoms of an aliphatic acyl group, 1-10 are preferable. Examples of such aliphatic acyl groups include acetyl, propanoyl, and butan oil.

As for the carbon atom number of an aliphatic acyloxy group, 1-10 are preferable. Examples of such aliphatic acyl groups include acetoxy.

As for the number of carbon atoms of an aliphatic acyl group, 1-8 are preferable. Such alkoxy groups may further include substituents (such as alkoxy groups). Examples of alkoxy groups (including substituted alkoxy groups) include methoxy, ethoxy, butoxy, and methoxyethoxy.

As for the number of carbon atoms of an alkoxycarbonyl group, 2-10 are preferable. Examples of such alkoxycarbonyl groups include methoxycarbonyl and ethoxycarbonyl.

As for the carbon atom number of an alkoxycarbonylamino group, 2-10 are preferable. Examples of such alkoxycarbonylamino include methoxycarbonylamino and ethoxycarbonylamino.

As for the number of carbon atoms of an alkylthio group, 1-12 are preferable. Examples of such alkylthio groups include methylthio, ethylthio, and octylthio.

As for the number of carbon atoms of an alkylsulfonyl group, 1-8 are preferable. Examples of such alkylsulfonyl groups include methanesulfonyl and ethanesulfonyl.

As for the number of carbon atoms of an aliphatic amido group, 1-10 are preferable. Examples of such amido groups include acetamido.

As for the number of carbon atoms of an aliphatic sulfoamido group, 1-8 are preferable. Examples of such aliphatic sulfoamido groups include methanesulfonamido, butanesulfonamido, and n-octanesulfonamido.

As for the number of carbon atoms of an aliphatic substituted amino group, 1-10 are preferable. Examples of such aliphatic substituted amino groups include dimethylamino, diethylamino, and 2-carboxycytylamino.

As for the number of carbon atoms of an aliphatic substituted carbamoyl group, 2-10 are preferable. Examples of such aliphatic substituted carbamoyl groups include methylcarbamoyl and diethylcarbamoyl.

As for the number of carbon atoms of an aliphatic substituted sulfamoyl group, 1-8 are preferable. Examples of such aliphatic substituted sulfamoyl groups are methylsulfamoyl and diethylsulfamoyl.

As for the number of carboatoms of an aliphatic substituted ureido group, 2-10 are preferable. Examples of such aliphatic ureido groups include methylureido.

Examples of non-aromatic heterocyclic groups include piperidino and morpholino.

The molecular weight of the retardation expression agent is preferably 300 to 800.

In the present invention, rod-shaped or discotic compounds are used as retardation expression agents, and compounds having 1, 3, 5-triazine rings in addition to rod-shaped compounds having a linear molecular structure are particularly advantageously used. The term "straight molecular structure" means that the thermodynamic most stable structure of the rod-like compound is a straight line. The thermodynamic most stable structure can be determined by crystal structure analysis or molecular orbital calculation. For example, molecular orbital calculations can be made using a software program for molecular orbital calculations (e.g., WinMOPAC2000, manufactured by Fujitsu), thereby minimizing heat to form the intended compound. The molecular structure that can be determined can be determined. The expression “molecular structure is straight” means that the backbone of the most thermodynamically stable molecular structure forms an angle of 140 degrees or more.

As a rod-like compound having two or more aromatic rings, a compound represented by the following formula (1) is suitable:

Formula (1): Ar ¹ -L ¹ -Ar ²

In the formula (1), Ar ¹ and Ar ² each independently represent an aromatic group.

The term "aromatic group" as used herein is intended to include aryl groups (aromatic hydrocarbon groups), substituted aryl groups, aromatic heterocyclic groups, and aromatic substituted heterocyclic groups.

Aryl groups and substituted aryl groups are preferred for aromatic heterocyclic groups and aromatic substituted heterocyclic groups. The heterocyclic ring of the aromatic heterocyclic group is generally an unsaturated ring, preferably a 5-membered ring, a 6-membered ring, or a 7-membered ring, more preferably a 5- or 6-membered ring. Typically, each aromatic hetero ring has the largest double bond. It is preferable that a hetero atom can contain nitrogen, oxygen, or a sulfur atom inside, and it is more preferable that a hetero atom can contain a nitrogen or sulfur atom inside.

Examples of the aromatic ring of the aromatic group include a benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, trizole ring, pyridine ring, pyrimidine ring, and pyrazine ring. Of these rings, the benzene ring is preferred over the other rings.

Examples of the substituent of the substituted aryl group and the aromatic substituted heterocyclic group include halogen atom (F, Cl, Br, I), hydroxyl group, carboxyl group, cyano group, amino group, alkylamino group (e.g., methylamino, ethylamino, butyl Amino, dimethylamino), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (e.g., N-methylcarbamoyl, N-ethylcarbamoyl, N, N-dimethylcarbamoyl) Pamoyl group, alkyl sulfamoyl group (e.g., N-methylsulfamoyl, N-ethylsulfamoyl, N, N-dimethylsulfamoyl), ureido group, alkylureido group (e.g., N-notchureido) , N, N-dimethylureido, N, N, N'-trimethylureido), alkyl group (e.g., methyl, ethyl, propyl, butyl, pentyl, heptyl, octyl, isopropyl, s-butyl, t- Amyl, cyclohexyl, cyclopentyl), alkenyl groups (e.g. vinyl, allyl, hexenyl), alkynyl groups (e.g. ethynyl, butynyl), acyl groups (e.g. , Formyl, acetyl, butyryl, hequisanoyl, lauryl), acyloxy groups (e.g. acetoxy, butyryl oxy, hexanoyloxy, lauryloxy), alkoxy groups (e.g. methoxy , Ethoxy, propoxy, butoxy, pentyloxy, heptyloxy, octyloxy), aryloxy groups (e.g. phenoxy), alkoxycarbonyl groups (e.g. methoxycarbonyl, ethoxycarbonyl , Propoxycarbonyl, butoxycarbonyl, pentyl oxycarbonyl, heptyloxycarbonyl), aryloxycarbonyl group (e.g. phenoxycarbonyl), alkoxycarbonylamino group (e.g. butoxycarbonylamino , Hexyloxycarbonylamino), alkyl thio (e.g., methylthio, ethylthio, propylthio, butylthio, pentylthio, heptylthio, octylthio), arylthio group (e.g., phenylthio) , Alkylsulfonyl groups (e.g. methylsulfonyl, ethylsulfonyl, propylsulfonyl, butylsulfonyl, pen Tilsulfonyl, heptyl sulfonyl, octylsulfonyl), amido groups (eg, acetamido, butyl amido, hexylamido, laurylamido), and non-aromatic heterocyclic groups (eg, parent Leporino, pyrazinyl).

Among these substituents, a halogen atom, cyano group, carboxyl group, hydroxyl group, amino group, alkylamino group, acyl group, acyloxy group, amido group, alkoxycarbonyl group, alkoxy group, alkylthio group, and alkyl group are preferred among other substituents. The alkyl portion and alkyl group of the alkylamino group, the alkoxycarbonyl, the alkoxy group and the alkyl thi group may further have a substituent. Examples of the substituent of the alkyl moiety and the alkyl group include halogen atom, hydroxyl group, carboxyl group, cyano group, amino group, alkylamino group, nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group, sulfamoyl group, alkylsulfamo Diary, ureido group, alkylureido group, alkenyl group, alkynyl group, acyl group, acyloxy group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, alkoxycarbonylamino group, alkylthio group, arylthio group, alkyl It may also include a sulfonyl group, an amido group, and a non aromatic heterocyclic group. Among these substituents, halogen atoms, hydroxyl groups, amino groups, alkylamino groups, acyl groups, acyloxy groups, acylamino groups, alkoxycarbonyl groups, and alkoxy groups are more preferable than others.

In formula (1), L ¹ is a divalent linking group selected from an alkylene group, an alkenylene group, an alkynylene group, -0-, -CO-, and a combination of two or more thereof. Achillen groups may also have a ring structure. As a cycloalkylene group, a cyclohexylene group, especially 1, 4- cyclohexylene is suitable. As open chain alkylene groups, straight chain alkylene groups are preferred for branched chain alkylene groups. The number of carbon atoms in such an alkylene group is preferably 1 to 20, more preferably 1 to 15, still more preferably 1 to 10, still more preferably 1 to 8, and most preferably 1 to 1 6.

It is preferable that the alkenylene group and alkynylene group which have an open chain structure have a ring structure, and the akenylene group and alkynylene group which have a linear chain structure are more preferable to those which have a branched chain structure. The number of carbon atoms of such an alkenylene group and the number of carbon atoms of such an aquinylene group are preferably 2 to 10, more preferably 2 to 8, still more preferably 2 to 6, even more preferably 2 To 4, particularly preferably 2 (vinylene or ethynylene).

As for the number of carboatoms of such an aryl group, 6-20 are preferable, More preferably, it is 6-16, More preferably, it is 6-12.

As for the angle which Ar <^1> and Ar <^2> which oppose over L <^1> form, at least 140 degree is preferable.

As a rod-shaped compound, the compound represented by following formula (2) is more suitable.

Formula (2): Ar ^l -L ² -XL ³ -Ar ²

In the formula (2), Ar ¹ and Ar ² are independent aromatics. Definitions and examples of aromatic groups such as Ar ¹ and Ar ² are the same as those of formula (1).

In formula (2), L ² and L ³ Each represents a divalent bonding group selected from an alkylene group, -O-, -CO-, or a combination of two or more thereof. Regarding the alkylene group, an alkylene group having an open chain structure is preferable to an alkylene group having a ring structure, and a straight chain alkylene group is more preferable to a branched alkylene group.

The number of carbon atoms of such an alkylene group is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, and particularly preferably 1 to 4. However, 1 or 2 (corresponding to methylene or ethylene) are most preferred.

L ² and L ³ For each, -O-CO- or -CO-O- is most appropriate.

In formula (2), X is 1, 4- cyclohexylene, vinylene, or ethynylene. Examples of the compound represented by formula (1) are shown below.

Exemplary compounds (1) to (34), (41), and (42) each have two asymmetric carbon elements in the 1-position and 4-position. However, exemplary compounds (1), (4) to (34), (41) and (42) have symmetric meso-shaped molecular structures, so none of them have optical isomers (optical activity), respectively Has only geometric isomers (trans and cis). Exemplary compounds (1) of the trans form (1-trans) and cis form (1-cis) are shown below.

As mentioned above, the rod-like compound for use in the present invention preferably has a straight structure. Thus, trans-type compounds are preferred for cis-type compounds.

Each of Exemplary Compounds (2) and (3) has optical isomers in addition to geometric isomers (four isomers in total). With regard to the geometric isomers, the trans form is preferred for the cis form as mentioned above. However, with respect to the optical isomers, it is not worth mentioning that some are better than others. Therefore, it may have any of the dextrose (D), the levo (L), and the racemic type.

In each of the exemplary compounds (43) to (45), the vinylene bond in the center, which may be either the trans form or the cis form, preferably has a trans form for the same reasons as mentioned above.

Other suitable compounds are shown below.

Two or more rod-like compounds whose maximum absorption wavelength (λ max) is shorter than 250 nm in the state of the ultraviolet absorption spectrum of the solution may be used in combination.

Rod-like compounds can be synthesized with reference to the methods described in the literature. Examples of such documents are described in Mol . Cryst . Liq . Cryst . , Vol. 53, p. 229 (1979), vol. 89, p. 93 (1982), vol. 145, p. 111 (1987), vol. 17O, p. 43 (1989), J. Am. Chem . Soc . , Vol. 113, p. 1349 (1991), p. 118, p. 5346 (1996), p. 92, p. 1582 (1970), J. 0 rg . Chem . , 40, 420 pages (1975), and Tetrahedron, 48, 16, 3437 pages (1992).

The addition amount of the retardation expression agent is preferably 0.1% by mass to 30% by mass, more preferably 0.5% by mass to 20% by mass, based on the amount of the polymer used.

The aromatic compound mentioned above is preferably 0.01 to 20 parts by mass, more preferably 0.05 to 15 parts by mass, and particularly preferably 0.1 to 10 parts by mass, per 100 parts by mass of cellulose acylate. As mentioned above, two or more aromatic compounds may be used in combination.

The organic solvent in which cellulose acylate is dissolved is described in detail below.

(Chlorine solvent)

In preparing the cellulose acylate solution of the present invention, a chlorine organic solvent is preferably used as the main solvent. In the present invention, the kind of the chlorine-based organic solvent is not particularly limited as long as the cellulose acylate can achieve its purpose within the range in which flow casting or film formation can be performed. These chlorine organic solvents are preferably dichloromethane and chloroform, with dichloromethane being particularly preferred. In addition to the chlorine-based organic solvent, mixing with an organic solvent is not particularly limited. In that case, dichloromethane needs to be used in an amount of at least 50% by mass. Non-chlorine organic solvents used in combination with chlorine organic solvents are described below. In other words, the non-chlorine organic solvent is a solvent selected from esters having 3 to 12 carbon atoms, ketones, ethers, and hydrocarbons. Esters, ketones, ethers, and hydrocarbons may have a cyclic structure. Esters, ketones, ethers, and hydrocarbons have a ring structure. Compounds having any two or more of esters, ketones, and ether functional groups (ie, -0-, -CO-, and -CO0-) can also be used as the solvent. For example, the solvent may simultaneously have other functional groups such as alcoholic hydroxyl groups. In the case of a solvent having two or more kinds of functional groups, the number of carbon atoms in the solvent may be within a specified range for the compound having any of the functional groups. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexane. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole, and phentol Include. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol, and 2-butoxyethanol.

The alcohol used in combination with the chlorine-based organic solvent is preferably a straight chain, a branched chain, or a ring, and among these, saturated aliphatic hydrocarbons are preferable. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol, and cyclohexanol. As alcohols, fluorine-based alcohols are also used. Examples include fluoroethanol, 2,2,2-trifluoroethanol, and 2,2,3,3-tetrafluoro-1-propanol. Moreover, the hydrocarbon may be straight chain, branched chain, or ring. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. Aliphatic hydrocarbons may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene, and xylene.

The combination of the chlorine-based organic solvent preferably used as the main solvent of the present invention is not limited to the following.

Dichloromethane / methanol / ethanol / butanol (75/10/5/5/5, parts by mass),

Dichloromethane / acetone / methanol / propanol (80/10/5/5, parts by mass),

Dichloromethane / methanol / butanol / cyclohexane (75/10/5/5 by mass),

Dichloromethane / methyl ethyl ketone / methanol / butanol (80/10/5/5, parts by mass),

Dichloromethane / acetone / methyl ethyl ketone / ethanol / isopropanol (75/8/5/5/7, parts by mass)

Dichloromethane / cyclopentanone / methanol / isopropanol (80/7/5/8, parts by mass)

Dichloromethane / methyl acetate / butanol (80/10/10, parts by mass),

Dichloromethane / cyclohexanone / methanol / hexane (70/20/5/5, parts by mass),

Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),

Dichloromethane / 1,3-dioxolane / methanol / ethanol (70/20/5/5, parts by mass),

Dichloromethane / dioxane / acetone / acetone / methanol / ethanol (60/20/10/5/5, parts by mass),

Dichloromethane / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5, parts by mass),

Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (70/10/10/5/5, parts by mass),

Dichloromethane / acetone / ethyl / acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass),

Dichloromethane / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass),

Dichloromethane / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass).

(Non-chlorine solvent)

Then, the non-chlorine organic solvent used for preparing the solution of the cellulose acylate of this invention is used preferably. In the present invention, the non-chlorine organic solvent is not particularly limited as long as the cellulose acylate can achieve the object in the range capable of flow casting or film formation. The non-chlorine organic solvent used in the present invention is preferably a solvent selected from esters, ketones and ethers each having 3 to 12 carbon atoms. Esters, ketones, ethers, hydrocarbons may have a ring structure. Compounds having two or more of the functional groups of esters, ketones, and ethers (ie, -O-, -CO-, and -COO-) can also be used as the main solvent. For example, the solvent may have other functional groups such as alcoholic hydroxyl groups. In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms in the solvent may be within a specific range for the compound having several functional groups. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexane. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole, and phentol Include. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol, and 2-butoxyethanol.

The non-chlorinated organic solvents used in the above-mentioned cellulose acylate are selected from the various aspects described above, but the following is preferable. That is, the preferable solvent of the cellulose acylate used for this invention is three or more types of mixed solvent different from each other. The first solvent is at least one solvent selected from methyl acetate, ethyl acetate, methyl formate, ethyl formate, acetone, dioxolane, dioxane, or a mixed solution thereof. The second solvent is selected from ketones and acetoacetic acid esters having 4 to 7 carbon atoms. The third solvent is selected from alcohols or hydrocarbons having 1 to 10 carbon atoms, more preferably alcohols having 1 to 8 carbon atoms. When the first solvent is a mixed solution of two or more solvents, the second solvent is not used. The first solvent is preferably methyl acetate, acetone, methyl formate, ethyl formate, or mixtures thereof, and the second solvent is methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl acetylacetate, or a mixed solution thereof. desirable.

The alcohol and the third solvent may be linear, branched, or cyclic, and among them, saturated aliphatic hydrocarbons are preferable. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol, and cyclohexanol. As the alcohol, fluorine-based alcohol can also be used. Examples include 2-fluoroethanol, 2,2,2-trifluoroethanol, and 2,2,3,3-tetrafluoro-1-propanol. Moreover, the hydrocarbon may be straight chain, branched chain, or ring. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. Aliphatic hydrocarbons may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene, and xylene. The alcohol and the hydrocarbon and the third solvent may be used alone or in combination of two or more, and are not particularly limited. Specific preferred examples of the third solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and cyclohexanol; Hydrocarbons such as cyclohexane and hexane. In particular, methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol are preferred.

The mixed solvent consisting of the above-mentioned three kinds of solvents includes a first solvent in an amount of 20% by mass to 95% by mass, a second solvent in an amount of 2% by mass to 60% by mass, and an agent in an amount of 2% by mass to 30% by mass It is preferable to include 3 solvents. More preferably, the mixed solvent contains a first solvent in an amount of 30% by mass to 90% by mass, a second solvent in an amount of 3% by mass to 50% by mass, an alcohol or a third solvent in an amount of 3% by mass to 25% by mass It is desirable to. Especially preferably, the mixed solvent comprises a first solvent in an amount of 30% by mass to 90% by mass, a second solvent in an amount of 3% by mass to 30% by mass, and an alcohol or a third solvent in an amount of 3% by mass to 15% by mass. It is preferable to contain. When the first solvent is a mixed solution and no second solvent is used, the mixed solvent preferably contains the first solvent in an amount of 20% by mass to 90% by mass and a third solvent in an amount of 5% by mass to 30% by mass. Do. More preferably, the mixed solvent includes a first solvent in an amount of 30 to 86 mass% and a third solvent in an amount of 7 to 25 mass%. The above-mentioned non-chlorinated organic solvents used in the present invention are described in more detail in JIII Journal of Technical Disclosure No. 2001-1745, pages 12-16 (published May 15, 2001, Japan Institute of Invention and Innovation). . Preferred combinations of the non-chlorinated organic solvents used in the present invention are not limited to the following.

Methyl acetate / acetone / methanol / ethanol / butanol (75/10/5/5/5, parts by mass),

Methyl acetate / acetone / methanol / ethanol / propanol (75/10/5/5/5, parts by mass),

Methyl acetate / acetone / methanol / butanol / cyclohexane (75/10/5/5/5 by mass),

Methyl acetate / acetone / ethanol / butanol (81/8/7/4 by mass),

Methyl acetate / acetone / ethanol / butanol (82/10/4/4, parts by mass),

Methyl acetate / acetone / ethanol / butanol (80/10/4/6 parts by mass),

Methyl acetate / methyl ethyl ketone / methanol / butanol (80/10/5/5 by mass),

Methyl acetate / acetone / methyl ethyl ketone / ethanol / isopropanol (75/8/5/5/7, parts by mass),

Methyl acetate / cyclopentanone / methanol / isopropanol (80/7/5/8 by mass),

Methyl acetate / acetone / butanol (85/10/5, parts by mass),

Methyl acetate / cyclopentanone / acetone / methanol / butanol (60/15/14/5/6, parts by mass),

Methyl acetate / cyclohexanone / methanol / hexane (70/20/5/5, parts by mass),

Methyl acetate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),

Methyl acetate / 1,3-dioxolane / methanol / ethanol (70/20/5/5, parts by mass),

Methyl acetate / dioxane / acetone / methanol / ethanol (60/20/10/5/5, parts by mass),

Methyl acetate / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane

 (65/10/10/5/5/5 mass parts),

Methyl formate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),

Methyl formate / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass),

Acetone / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass),

Acetone / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass),

Acetone / 1,3-dioxolane / ethanol / butanol (65/20/10/5, parts by mass), and

1,3-dioxolane / cyclohexanone / methyl ethyl ketone / methanol / butanol (55/20/10/5/5/5, parts by mass).

Furthermore, cellulose acylate solutions prepared by the following methods may be used:

Preparing a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (81/8/7/4, parts by mass), and further adding 2 parts by mass of butanol after filtration and concentration; Preparing a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (84/10/4/2 mass parts), and further adding 4 parts by mass butanol after filtration and concentration; A cellulose acylate solution is prepared with methyl acetate / acetone / ethanol (84/10/6, parts by mass), and 5 parts by mass of butanol is further added after filtration and concentration.

(Characteristics of Cellulose Acylate Solution)

The cellulose acylate solution used in the present invention is preferably in an organic solvent in an amount of 10% by mass to 30% by mass, more preferably 13% by mass to 27% by mass, particularly preferably 15% by mass to 25% by mass. It is characterized by dissolving cellulose acylate. As a method of adjusting the cellulose acylate solution to these concentrations, it may be made to a predetermined concentration in the step of dissolving the solution, or prepared in a low concentration solution (for example, 9% by mass to 14% by mass) in advance It may be adjusted to a predetermined high concentration solution in the concentration step. Furthermore, after preparing a high concentration cellulose acylate solution in advance, a predetermined low concentration cellulose acylate solution is prepared by adding various additives. Whichever method is used, there is no particular problem as long as the concentration of the cellulose acylate of the present invention is obtained.

In the present invention, it is preferable that the aggregate molecular weight of the cellulose acylate of the solution obtained by diluting the cellulose acylate solution to a concentration of 0.1% by mass to 5% by mass with an organic solvent having the same composition as the solution is 150,000 to 15,000,000. More preferably, the association molecular weight is 180,000 to 9,000,000. Association molecular weight can be determined by the static light scattering method. It is preferable that the cellulose acylate is dissolved so that the square radius of inertia determined at that time is 10 nm to 200 nm. Furthermore, the cellulose acylate is dissolved such that the second virtual coefficient is preferably -2x10 ^-4 to 4x10 ^-4 , more preferably -2x10 ^-4 to 2x10 ^-4. do. The definition of the association molecular weight, the square radius of inertia, and the second vireal coefficient are described. These were measured using the static light scattering method according to the following process. Measurements were made in the lean region of the device. However, these measurements reflect the action of dope in the high concentration region of the present invention. First, cellulose acylate was dissolved in the solvent used for dope, and the solution of 0.1 mass%, 0.2 mass%, 0.3 mass%, and 0.4 mass% was prepared. In order to prevent moisture absorption, the cellulose acylate was previously dried at 120 ° C. for 2 hours, and then weighed at 25 ° C. and 10% RH. Dissolution was performed in accordance with the method (normal temperature dissolution method, cooling dissolution method, high temperature dissolution method) used at the time of dope dissolution. As a result, these solutions and solvents were filtered through a 0.2-μm Teflon filter. And the static light scattering of the filtered solution was measured in 10 degree intervals from 25 degreeC to 30 degree-140 degree using the light scattering measuring apparatus (DLS-700, Otsuka Electroincs Co., Ltd. product). The data obtained were interpreted according to the Berry plotting method. The refractive index required for this analysis uses the value of the solvent determined by Abbe's refractometer, and the concentration gradient (dn / dc) is used for measuring light scattering using a differential refractometer (DRM-102l, Otsuka Elecronics Co., Ltd). It measured using the solvent solution.

(Dope preparation)

Next, in the preparation of the cellulose acylate solution (dope) of the present invention, the dissolution method is not particularly limited. The dope may be prepared at room temperature or by a cooling dissolution method, a high temperature dissolution method, or a combination thereof. As for these, for example, JP-A-5-163301, JP-A-61-106628, JP-A-58-127737, JP-A-9-95544, JP-A Japanese Patent Laid-Open No. 10-95854, Japanese Patent Laid-Open No. 10-45950, Japanese Patent Laid-Open No. 2000-53784, Japanese Patent Laid-Open No. 11-322946, Japanese Patent Laid-Open No. 11-322947, Japanese Patent Laid-Open Japanese Patent Laid-Open No. 2-276830, Japanese Patent Laid-Open No. 2000-273239, Japanese Patent Laid-Open No. 11-71463, Japanese Patent Laid-Open No. 4-259511, Japanese Patent Laid-Open No. 2000-273184, and Japanese Patent Laid-Open Japanese Unexamined Patent Application Publication No. 11-323017 and Japanese Unexamined Patent Application Publication No. 11-302388 disclose a method for preparing a cellulose acylate solution. The above-mentioned method of dissolving cellulose acylate in an organic solvent can be suitably applied to the present invention as long as it is within the scope of the present invention. Their details, in particular non-chlorine solvent systems, are described in JIII Journal of Technical Disclosure No. 2001-1745, pages 7 to 12 (published May 15, 2001, Japan Institute of Invention and Innovation). Moreover, the cellulose acylate dope solution used in the present invention is usually concentrated and filtered, the details of which are described in JIII Journal of Technical Disclosure No. 2001-1745, page 25 (published May 15, 2001). , Japan Institute of Invention and Innovation). When dissolved at a high concentration, when dissolved at a high temperature, most of the cellulose acylate is always dissolved above the boiling point of the organic solvent used. In that case, it dissolves under pressure.

In the cellulose acylate solution used in the present invention, the viscosity and the dynamic storage modulus of the solution are preferably within a certain range. One milliliter of sample solution was measured by using a rheometer (CLS 500) having a steel cone with a diameter of 4 cm / 2 ° (both manufactured by TA Instruments Inc.). The measurement condition is that the Oscillation Step / Temperature Ramp is changed at a rate of 2 ° C./min within a range of 40 ° C. to −10 ° C., and is a static non-Newtonian at 40 ° C. The storage modulus G '(Pa) is determined at the viscosity n * (Pa · s) and -5 ° C. After the temperature of the sample solution was kept at a measurement start temperature in advance until the temperature of the liquid became constant, the measurement was started. In the present invention, the viscosity at 40 ° C. is preferably 1 to 400 Pa · s, and the dynamic storage modulus at 500 ° C. is preferably 500 Pa or more. More preferably, the viscosity in 40 degreeC is 10 Pa.s-200 Pa.s, and the dynamic storage elastic modulus in 15 degreeC is 100-1,000,000 Pa. Moreover, higher dynamic storage modulus at lower temperatures is desirable. For example, when the temperature of the flow casting support is -5 ° C, the dynamic storage elastic modulus at -5 ° C is preferably 10,000 to 1,000,000 Pa, and when the temperature of the support is -50 ° C, the dynamic storage at -50 ° C The modulus of elasticity is preferably 10,000 to 5,000,000 Pa.

As described above, the cellulose acylate solution has a high concentration of dope, and is characterized in that a cellulose acylate solution having high concentration and excellent stability is obtained without resorting to the concentration means. In order to more easily dissolve, the cellulose acylate may be dissolved at a low concentration, and then such a solution may be concentrated using a concentration means. There is no particular limitation on the concentration method, but for example, introducing a low concentration solution between the cylinder and a rotational trajectory formed by the outer periphery of the rotary vane rotating in the circumferential direction inside the cylinder, thereby providing a temperature difference between the cylinder and the solution. A method of obtaining a high concentration solution while evaporating a solvent comprising a step of giving (for example, Japanese Patent Application Laid-open No. Hei 4-259511), ejecting a heated low concentration solution from the nozzle to the chamber, and the solution is released from the nozzle to the inner wall of the chamber. Performing flash evaporation of the solvent until it impinges the process, simultaneously removing the solvent vapor from the chamber, and withdrawing the high concentration solution (e.g., US Pat. No. 2,541,012, US Pat. No. 2,858,229, US The method described in Patent No. 4,414,341, and US Patent No. 4,504,355).

Prior to flow casting, it is desirable to remove undissolved matter, foreign matter such as dust and impurities from the solution by filtration through suitable filtration media such as metal mesh (wire mesh) and flannel. For filtration of the cellulose acylate solution, a filter having an absolute filtration accuracy of 0.1 to 100 µm is used, and a filter having an absolute filtration accuracy of 0.5 to 25 µm is more preferably used. The thickness of the filter is preferably in the range of 0.1 mm to 10 mm, more preferably in the range of 0.2 mm to 2 mm. In that case, the filtration pressure is preferably filtered at 16 kgf / cm ² or less, more preferably 12 kgf / cm ² or less, still more preferably 10 kgf / cm ² or less, particularly preferably ² kgf / cm ² or less. . As the filter medium, conventionally known materials such as fluoro resins such as glass fibers, cellulose fibers, filter papers, tetrafluoroethylene resins and the like are used. In particular, a ceramic, a metal, etc. are used preferably. The viscosity just before film formation of a cellulose acylate solution may be arbitrary as long as it is the range which can flow-cast at the time of film formation. Usually, it is preferably in the range of 10 Pa · s to 2,000 Pa · s, more preferably in the range of 30 Pa · s to 1,000 Pa · s, still more preferably in the range of 40 Pa · s to 500 Pa · s A cellulose acylate solution is prepared to have a viscosity. The temperature at this time will not be specifically limited if it is the temperature at the time of flow casting. However, Preferably it is -5 degreeC-70 degreeC, More preferably, it is -5 degreeC-55 degreeC.

(Film formation)

The manufacturing method of the film using a cellulose acylate solution is demonstrated. As a method and apparatus for producing the cellulose acylate film of the present invention, a solution casting film forming method and a solution casting film forming apparatus used in the conventional cellulose triacetate film production are used. The dope (cellulose acylate solution) prepared from the dissolution apparatus (pot) is once stored in the storage port, and the final adjustment is performed by defoaming the bubbles contained in the dope. The dope is sent from the dope outlet to a pressurized die, for example via a pressurized metering gear pump that can send metering very precisely by its rotational speed. The dope is homogeneously casted onto the metal support of the flexible part which is constantly running from the cap (slit) of the press die, and the metal support peels off the semi-dried dope film (also called web) from the metal support at about one turn. . Both ends of the web thus obtained are picked up with a clip, and the web is conveyed by a tenter while maintaining the width, and dried. As a result, the web is returned to the roll group of the drying apparatus to complete drying and take a predetermined length with the winder. The combination with the tenter and drying apparatus equipped with the roll group may vary depending on the purpose. In the solution casting film forming method used for producing a film for an electronic display device, not only the solution casting film forming apparatus, but also the surface treatment of the film provided with layers such as a serving layer, an antistatic layer, an antihalation layer, and a protective layer Often a coater is added for. Although each manufacturing process is briefly described below, it is not limited to these.

First, when a cellulose acylate film is prepared by the solution cast method, a cellulose acylate solution (dope) is cast on a drum or a band, and the solution is evaporated there, thereby forming a film. It is preferable to adjust the concentration of the dope before the flow casting so that the solid amount is from 5% by mass to 40% by mass. The surface of the drum or band is preferably finished in a mirror smooth state. The dope is preferably cast on a drum or band having a surface temperature of 30 ° C or lower. In particular, the metal support temperature of -10 degreeC-20 degreeC is preferable. Furthermore, Japanese Patent Laid-Open No. 2000-301555, Japanese Patent Laid-Open No. 2000-301558, Japanese Patent Laid-Open No. 7-032391, Japanese Patent Laid-Open No. 3-193316, Japanese Patent Laid-Open No. 5-086212 Japanese Patent Application Laid-Open No. 62-037113, Japanese Patent Application Laid-Open No. 2-276607, Japanese Patent Application Laid-open No. 55-014201, Japanese Patent Application Laid-open No. 2-111511, and Japanese Patent Application Laid-open No. 2--276607 The present invention can be applied to the technique described in 208650.

(Multilayer Flow Casting)

The cellulose acylate solution may be cast in a single layer on a smooth band or drum that serves as a metal support, or a plurality of cellulose acylate solutions may be cast in two or more layers. When casting a plurality of cellulose acylate solutions, a film may be prepared by sequentially casting the cellulose acylate containing solution from each of the plurality of casting dies disposed at intervals in the advancing direction of the metal support and stacking them. For example, the methods described in Japanese Patent Application Laid-Open No. 61-158414, Japanese Patent Application Laid-Open No. 1-122419, and Japanese Patent Application Laid-Open No. 11-198285 can be adopted. Moreover, a film may be formed by casting a cellulose acylate solution from two casting dies, for example, JP-A-60-27562, JP-A-61-94724, JP-A-JP This can also be performed by the method of 61-947245, Unexamined-Japanese-Patent No. 61-104813, Unexamined-Japanese-Patent No. 61-158413, and Unexamined-Japanese-Patent No. 6-134933. Moreover, the cellulose acylate film casting which wraps the flow of the high viscosity cellulose acylate solution described in JP-A-56-162617 with a low viscosity cellulose acylate solution, and simultaneously extrudes both the high viscosity and the low viscosity cellulose acylate solution The method may be used. In addition, preferred embodiments allow the outer solution described in JP-A-61-94724 and JP-A-61-94725 to contain more alcohol components, which are poorer solvents, than the inner solution. to be. Alternatively, two casting dies may be used to peel off the film formed on the metal support from the first casting die and to perform a second casting on the side of the film in contact with the metal support surface, whereby the film is Are manufactured. This method is described in Japanese Patent Laid-Open No. 44-20235. The cellulose acylate solution to be cast may be the same or different, and is not particularly limited. In order to have a function in the plurality of cellulose acylate layers, a cellulose acylate solution according to each function may be extruded from the casting die, respectively. Furthermore, the cellulose acylate solution can also be cast together with other functional layers (eg, adhesive layers, dye layers, antistatic layers, antihalation layers, U V absorbing layers, and polarizing layers) at the same time.

In conventionally known monolayer solutions, in order to obtain the desired film thickness, it is necessary to extrude a cellulose isylate solution having a high concentration and a high viscosity. In that case, the stability of the cellulose acylate solution is deteriorated, and solids are generated, causing spot failures and poor planarity, which in many cases cause problems. To solve this problem, by casting a plurality of cellulose acylate solutions from a casting die, a solution of high viscosity can be extruded simultaneously on a metal support. Not only can the film be improved in planarity and have a good face quality, but the use of the concentrated cellulose acylate solution can reduce the dry load and increase the yield of the film.

In the case of cocasting, the thickness of the inner side and the outer side is not particularly limited. However, the thickness of the outer layer is preferably 1% to 50% of the total film thickness, more preferably 2% to 30%. In the case of three or more layers of cocasting, the total film thickness of the layer in contact with the metal support and the layer in contact with the air is defined as the outer film thickness. In the case of cocasting, a cellulose acylate film having a laminated structure can also be prepared by cocasting cellulose acylate solutions having different additive concentrations such as the above-mentioned plasticizers, UV absorbers, or matting agents. . For example, the cellulose acylate film which has a structure of a skin layer / core layer / skin layer can be manufactured. For example, the matting agent may be added to the skin layer in an amount larger than the core layer, or only to the skin layer. The plasticizer and the ultraviolet absorbent may be added in a larger amount to the core layer than the skin layer, or may be added only to the core layer. Additionally, the kind of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer. For example, a low volatile plasticizer and / or an ultraviolet absorber can be added to the skin layer, and a plasticizer excellent in plasticity or a UV absorber excellent in UV absorption can be added to the core layer. Moreover, it is also a preferred embodiment to add a releasing agent only to the skin layer on the metal support side. Furthermore, in order to cool the metal support by the cooling drum method to gel the solution, it is also preferable to add an amount of the poor solvent alcohol to the skin layer more than the core layer. Tg of a skin layer and a core layer may differ, and it is preferable that Tg of a core layer is lower than Tg of a skin layer. In addition, the viscosity of the cellulose acylate-containing solution during casting may be different between the skin layer and the core layer. Although it is preferable that the viscosity of a skin layer is lower than the viscosity of a core layer, the viscosity of a core layer may be lower than the viscosity of a skin layer.

(Flow casting)

A method of casting a solution, comprising: uniformly extruding a prepared dope from a press die onto a metal support, a doctor blade method of controlling the film thickness of a dope once cast on a metal support, or a reverse rotation of the film thickness There is a reverse roll coater method to control the roll. Of course, a method using a press die is preferred. Pressurized dies include coat hanger type and T-die type dies, both of which can preferably be used. In addition to the methods described herein, various methods of casting a known cellulose triacetate solution to form a film can be used. By setting the respective conditions in consideration of the difference in boiling point or similarity of the stages of the solutions used, an effect similar to that described in each publication is obtained. As the endlessly running metal support used to make the cellulose acylate film of the present invention, a drum mirror finished with a chrome-plated surface or a stainless belt mirror (which may be called a band) finished by surface polishing is used. . As the press die used in the production of the cellulose acylate film of the present invention, two or more dies may be provided on the metal support. One or two dies are preferred. When two or more dies are installed, the amount of dope to cast may be split into each die at various rates, or may be dope to the dies at respective rates from a plurality of precision metering gear pumps. The temperature of the cellulose acylate solution used in the flow casting is preferably -10 ° C to 55 ° C, more preferably 25 ° C to 50 ° C. In that case, the temperature may be the same for all steps or may be different in each step. When the temperatures are different, only a predetermined temperature is required just before casting.

(dry)

A method of drying a dope onto a metal support in the production of a cellulose acylate film, which generally comprises a method of receiving hot air from the surface side of the metal support (drum or belt), ie from the surface of the web on the metal support; A method of catching hot air from the back of the drum or belt; And a liquid heat transfer method in which the temperature controlled liquid is brought into contact with the drum or the belt at the back surface opposite the dope casting surface of the belt or the drum, and the drum or the belt is heated by heat transfer to control the surface temperature. However, the backside liquid heat transfer method is preferred. The surface temperature of the metal support before fluid casting may be arbitrary as long as it is below the boiling point of the solvent used for dope. However, in order to promote drying and to reduce the fluidity on the metal support, it is preferable to set the temperature at 1 to 10 ° C. lower than the boiling point of the solvent having the highest boiling point among the solvents used. The above content does not apply when the cast dope is peeled off without drying after cooling.

(Stretching processing)

In the cellulose acetate film of the present invention, the retardation can be adjusted by the stretching treatment. Moreover, the method of positively stretching a film in the width direction, for example, Unexamined-Japanese-Patent No. 62-115035, Unexamined-Japanese-Patent No. 4-152125, Unexamined-Japanese-Patent No. 4-284211, Unexamined-Japanese-Patent No. Japanese Patent Application Laid-Open No. 4-298310 and Japanese Laid-Open Patent Publication No. 11-48271. In order to increase the in-plane retardation value of the cellulose acylate film, the produced film is stretched.

Stretching of a film is performed under normal temperature or heating conditions. It is preferable that heating temperature is below the glass transition temperature of a film. Stretching of a film may be longitudinal or transverse uniaxial stretching only, or simultaneous or sequential biaxial stretching. Stretching is carried out at a rate of 1% to 200%, preferably 1% to 100%, particularly preferably 1% to 50%. As for the birefringence of an optical film, it is appropriate that the refractive index of the width direction becomes larger than the refractive index of the longitudinal direction. Therefore, it is preferable to stretch a film more in the width direction. In addition, the stretching treatment may be carried out in the course of film formation, or may be carried out after the whole film formed is rolled up in the form of a web. In the former case, the stretching treatment can be carried out as a film formed still containing the residual solvent, and the film formed with the internal solvent residual amount of 2 to 30% can be preferably stretched.

The thickness of the finished (after drying) cellulose acylate film is usually 5 µm to 500 µm, preferably 20 µm to 300 µm, and particularly preferably 40 µm to 180 µm, depending on the end use purpose. In particular, for VA liquid crystal display devices, the film thickness is suitably 40 µm to 110 µm. Alternatively, the film thickness is also preferably adjusted in the range of 110 μm to 180 μm. In this range, water becomes difficult to pass through the film. Therefore, a film having such a thickness is advantageous and preferable for a polarizing plate durability test of 500 hours under conditions of 60 ° C and 95% RH. This is because the magnitude of the optical characteristic is proportional to the film thickness and the moisture permeability decreases in inverse proportion to the thickness, so that the larger the film thickness, the lower the moisture permeability.

The film thickness may be controlled by adjusting the solid concentration contained in the dope, the spacing between slits of the cap of the die, the extrusion pressure from the die, the speed of the metal support, and the like so as to obtain a desired thickness. The width of the cellulose acylate film thus obtained is preferably 0.5 m to 3 m, more preferably 0.6 m to 2.5 m, still more preferably 0.8 m to 2.2 m. The length of the film is preferably wound around 100 m to 10, OO m per roll, more preferably 500 m to 7,000 m, still more preferably 1,000 m to 6,000 m. When taking out the film, it is preferred that knurling be given to one or more ends of the film. Its width is from 3 mm to 50 mm, preferably from 5 m to 30 mm. The height is 0.5 µm to 500 µm, and preferably 1 µm to 200 µm. This may be a one side press or a two layer process. Furthermore, the change in Re value over the entire width is preferably within ± 5 nm, more preferably within ± 3 nm. Moreover, the change in the Rth value is preferably within ± 10 nm, more preferably within ± 5 nm. The change in the Re value and the Rth value in the longitudinal direction is preferably within the change range in the width direction. In order to maintain transparency, the haze is appropriately controlled in the range of 0.01% to 2%. In order to reduce the haze, certain matting agents are required, which are sufficiently dispersed to reduce the number of aggregated particles, and which may be used alone in the skin layer to reduce the amount of addition.

(Optical Properties of Cellulose Acylate Film)

The Re value of the cellulose acylate film used in the present invention is preferably 20 nm to 150 nm. In order to effectively reduce the light leakage in the oblique direction of the IPS mode liquid crystal display, the Re value is more preferably in the range of 40 nm to 115 nm, more preferably in the range of 60 nm to 95 nm. In addition, the Rth / Re ratio is adjusted in the range of 1.5 to 7. In order to effectively reduce the light leakage in the oblique direction of the IPS mode liquid crystal display device, the Rth / Re ratio is more preferably in the range of 2.0 to 5.5, still more preferably in the range of 2.5 to 4.5.

Regarding the optical properties of the cellulose acylate film according to the present invention, in the OCB mode liquid crystal display device, the Re retardation value and the Rth retardation value preferably satisfy the following relationship (V) and (VI), respectively;

(V): 20 nm ≤ Re (550) ≤ 100 nm

(VI): 70 nm ≤ Rth (550) ≤ 350 nm

(Where Re (λ) is an in-plane retardation value expressed in units (nm) at wavelength (λ nm) and Rth (λ) is a thickness direction retardation value expressed in units (nm) at wavelength (λ nm)) .

It is more preferable that the Re retardation value and the Rth retardation value satisfy the following relationship (i) and (i);

(Iii): 30 nm ≤ Re (550) ≤ 70 nm

(Iii): 150 nm ≤ Rth (550) ≤ 250 nm

The Re (λ) value was measured by KOBRA 21ADH (manufactured by Oji Scientific Instruments) by injecting light having a wavelength (λ nm) into the film by a normal method at the film surface. In addition, the Rth (λ) value is a retardation value Re (λ) and a ritata measured by injecting light having a wavelength (λnm) from a direction inclined + 40 ° with respect to the normal direction of the film using the in-plane slow axis as an inclination axis. Retardation value measured in three different directions, which is a retardation value measured by injecting light of wavelength (λ nm) from a direction inclined at -40 ° with respect to the normal direction of the film, using the diation value and the in-plane slow axis as the inclination axis. Based on the above, the assumption value of the average refractive index 1.48 and the film thickness were input and calculated.

In this specification, λ is 550 nm unless otherwise stated.

The optical property values of Re and Rth change with changes in mass and dimensions due to changes in humidity and time lapse at high temperatures. The smaller the change in the Re and Rth values, the more suitable the film is for use. In order to reduce the change in optical properties due to humidity, in addition to using cellulose acylate having a high acyl substitution degree at the 6-position, hydrophobic additives (including plasticizers, retardation expression agents, and ultraviolet absorbers) may be used. The moisture permeability and the equilibrium moisture content become small. Suitable water vapor permeability is 400 g / m ² to 2,300 g / m ² as measured under conditions of 60 ° C., 95% RH, and 24 hours. Appropriate values measured at 25 ° C. and 80% RH with respect to the equilibrium moisture content are 3.4% or less. By changing the humidity from 10% RH to 80% RH at 25 ° C, it is preferable that the amount of change in the optical characteristics is 12 nm or less, and the amount of change in Rth is 32 nm or less. The amount of the preferred additive is preferably 10% by mass to 30% by mass, more preferably 12% by mass to 25% by mass, more preferably 14.5% by mass to 20% by mass of the amount of the cellulose acylate used. When the film's mass change or dimensional change occurs due to volatility or degradability contained in the additive, optical property change occurs. Therefore, it is preferable that the mass change amount of a film is 5% or less after passing 48 hours at 80 degreeC and 90% RH. Similarly, the amount of dimensional change of the film after elapse of 24 hours at 60 ° C. and 95% RH is preferably 5% or less. In addition, the amount of dimensional change after 24 hours and 24 hours at 90 ° C. and 5% RH is preferably 5% or less. Even if there is little dimensional change or mass change, when the photoelastic coefficient of a film is small, the amount of change of an optical characteristic becomes small. Therefore, the photoelastic coefficient of the film is preferably 50 × 10 ^-13 cm ² / dyne or less. The glass transition temperature Tg of the cellulose acylate film is preferably 80 ° C to 180 ° C. The elastic modulus of the cellulose acylate film is preferably 1,500 MPa to 5,000 MPa. Moreover, it is preferable that a cellulose acylate film contains microparticles of silicon dioxide which has an average secondary particle diameter of 0.2 micrometer-1.5 micrometers.

(Optical anisotropic layer)

The optically anisotropic layer is formed from the liquid crystal compound. The optically anisotropic layer can be formed directly on the surface of the transparent support. After forming the oriented film on the transparent support, it is also acceptable to form an optically anisotropic layer on the oriented film. Alternatively, the optical compensation film is prepared by forming the optically anisotropic layer from the liquid crystal compound on the separate substrate and then transferring the optically anisotropic layer to the transparent support. An adhesive layer may be previously provided in the transparent support body to which an optically anisotropic layer is conveyed.

Preferred examples of the liquid crystal compound include rod-shaped or discotic liquid crystal compounds. The rod-shaped or discotic liquid crystalline sulfide may be a polymer liquid crystal. In the formation of the optically anisotropic layer, the liquid crystal compound may lose liquid crystallinity by polymerization or crosslinking.

<Rod-shaped liquid crystalline compound>

Examples of the rod-like liquid crystalline compounds include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane, and cyano substituted phenyls. Pyrimidines, alkoxy substituted phenylpyrimidines, phenyldioic acids, tolans and alkenylcyclohexylbenzonitriles. Moreover, a metal complex is also contained in a rod-like liquid crystalline compound. In addition, a liquid crystalline polymer including a molecular structure corresponding to a rod-like liquid crystalline compound in a repeating unit may also be used. In other words, the rod-like liquid crystalline compound may form a liquid crystalline polymer by combining with a polymer.

Description of the rod-like liquid crystalline compound is described in, for example, Kikan Kagaku Sosetsu Quarterly Review of Chemistry, Volume 22 (Chemistry of Liquid Crystals, entitled "Ekisho no Kagaku"), chapters 4, 7 and 11, The Chemical Society of Japan (1994), and Ekisho Debaisu Handobukku (Handbook of Liquid Crytal Devices), chapter 3, The 142-th Commitee of Japan Society for the Promotion of Science.

It is preferable that the rod-like liquid crystal compound has its birefringence factor in the range of 0.001 to 0.7.

In order to fix the orientation state, it is preferable that a rod-shaped liquid crystalline compound has a polymeric group. An unsaturated polymerizable group or an epoxy is preferable, an unsaturated polymerizable group is more preferable, and an ethylenically unsaturated polymerizable group is especially preferable.

In layer formation, it is preferable that the molecules of the rod-like liquid crystalline compound used in the present invention are substantially vertically aligned, and fixed and formed in the alignment state thereof. As used herein, "substantially vertical" means that the angle between the film surface and the director of the rod-like liquid crystal compound is used within the range of 70 to 90 degrees.

These rod-like liquid crystalline molecules may be arranged obliquely, or may be arranged so that their inclination angles change gradually (hybrid orientation). In both oblique orientation and hybrid orientation, the average inclination angle is preferably 70 ° to 90 °, more preferably 80 ° to 90 °, and particularly preferably 85 ° to 90 °.

The optically anisotropic layer made of a rod-like liquid crystalline compound is a rod-like liquid crystalline compound, and if necessary, a coating liquid containing an additive containing the following polymerizable initiator and an air interface vertical aligning agent is formed on a vertical alignment film formed on a support. After apply | coating and making it orientate vertically, it can form by fixing the orientation state. The optically anisotropic layer can be formed by transferring a layer made of a rod-like liquid crystalline compound onto a cellulose acylate film. In order to obtain the intended optical properties, the optically anisotropic layer may be formed not only by one component layer but also by stacking two or more component layers. Alternatively, the optically anisotropic layer may be formed to satisfy the intended optical properties by laminating the support and the retardation film as a whole.

As a solvent used for preparation of a coating liquid, an organic solvent is used preferably. Examples of organic solvents include amides (such as N, N-dimethylformamide), sulfoxides (such as dimethyl sulfoxide), heterocyclic compounds (such as pyridine), hydrocarbons (such as phenene and hexane), Alkyl halides (such as chloroform and dichloromethane), esters (such as methyl acetate and butyl acetate), ketones (such as acetone and methyl ethyl ketone), ethers (such as tetrahydrofuran and 1,2-diketoxyethane) do. Of these solvents, alkyl halides and ketones are preferred over others. Two or more organic solvents may be used in combination. Application of the coating liquid can be carried out using a known method (such as extrusion coating, direct gravure coating, reverse gravure coating, and die coating method).

It is preferable that a vertical alignment liquid crystalline compound is fixed so that the orientation state may be maintained. Immobilization understands that a liquid crystalline compound molecule is fixed by the polymerization reaction of the polymeric group (P) introduce | transduced inside. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Here, photopolymerization reaction is more preferable than thermal polymerization reaction. Examples of photopolymerization initiators usable herein include α-carbonyl compounds (disclosed in US Pat. No. 2,367,661, US Pat. No. 2,357,670), acyloin ether (disclosed in US Pat. No. 2,448,828), α-hydro Carbon-substituted aromatic acyloin compounds (disclosed in US Pat. No. 2,722,512), multinuclear quinone compounds (disclosed in US Pat. No. 3,046,127, US Pat. No. 2,951,758), triaryl imidazole dimers and p-aminophenyl ketones; Combinations of US Pat. No. 3,549,367, acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850), and oxadiazole compounds (US Pat. 4,212,970).

As for the usage-amount of a photoinitiator, 0.01 mass%-20 mass% of solid content in a coating liquid are preferable, and 0.5 mass%-5 mass% are more preferable. For the polymerization of rod-like liquid crystalline molecules, it is preferable to use ultraviolet light for irradiation. The irradiation energy is preferably 20 mJ / cm ² to 50 J / cm ² , more preferably 100 mJ / cm ² to 80 mJ / cm ² . In order to promote the photopolymerization reaction, light irradiation may be carried out under heating conditions. 0.1 micrometer-10 micrometers are preferable, as for the thickness of the 1st retardation area | region containing an optically anisotropic layer, 0.5 micrometer-5 micrometers are more preferable, 1 micrometer-5 micrometers are especially preferable.

<< vertical orientation film >>

In order to orientate the liquid crystal compound vertically on the alignment film side, it is important to lower the surface energy of the alignment film. More specifically, the surface energy of the oriented film is lowered with the aid of the functional group of the polymer, whereby the liquid crystalline compound is brought upright. As a functional group which lowers the surface energy of an oriented film, the hydrocarbon group containing a fluorine atom and 10 or more carbon atoms per group is effective. In order to make a fluorine atom or a hydrocarbon group exist on the surface of an oriented film, it is appropriate to introduce the fluorine atom or hydrocarbon introduced into the side chain rather than the main chain of a polymer. The fluorine-containing polymer preferably contains fluorine atoms in a proportion of 0.05% by mass to 80% by mass, more preferably in a proportion of 0.1% by mass to 70% by mass, and in a proportion of 0.5% by mass to 65% by mass. It is more preferable to contain, and it is especially preferable to contain in the ratio of 1 mass%-60 mass%. Hydrocarbon groups are aliphatic groups, aromatic groups, or a combination of these groups. Aliphatic groups preferably have a ring structure, a branched chain, and a straight chain structure. The aliphatic group is preferably an alkyl group (including a cycloalkyl group) or an alkenyl group (including a cycloalkenyl group). The hydrocarbon group may have a substituent that does not exhibit strong hydrophilicity such as a halogen atom. 10-100 are preferable, as for the carbon atom number of each hydrocarbon group, 10-60 are more preferable, and 10-40 are especially preferable. The main chain of the polymer preferably has a polyimide structure or a polyvinyl alcohol structure.

Polyimides are generally synthesized by condensation reactions between tetracarboxylic acids and diamines. By increasing the use of various tetracarboxylic acids or diamines, polyimides equivalent to copolymers can also be synthesized. The fluorine atom or hydrocarbon group may be present in repeat units of tetracarboxylic acid origin, repeat units of diamine origin, or both. When introducing a hydrocarbon group into a polyimide, it is particularly preferable that a steroid structure is formed in the main chain or the side chain of the polyimide. The steroid structure present in the side chain is equivalent to a hydrocarbon group containing 10 or more carbon atoms and has a function of vertically aligning the liquid crystalline compound. As used herein, the term "steroid structure" refers to a cyclopentanone-hydrophenanthrene ring structure or a portion of the bond of which is modified to a double bond within the range of the aliphatic ring (without the formation of an aromatic ring by such modification). It refers to the ring structure which becomes.

As another method of vertically aligning the liquid crystalline compound, a method of mixing an organic acid with a polymer of polyvinyl alcohol, modified polyvinyl alcohol, or polyimide can be advantageously used. Examples of organic acids that can be suitably used for mixing include carboxylic acid, sulfonic acid, amino acid.

The thing which shows acidity among the air interface aligning agents mentioned later can also be used. In addition, quaternary ammonium salts may also be advantageously used. 0.1 mass%-20 mass% of the high molecular weight used are preferable, and, as for the mixing amount, 0.5 mass%-10 mass% are more preferable.

The saponification degree of the polyvinyl alcohol is preferably 70 to 100%, particularly preferably 80 to 100%, and the polymerization degree is preferably 100 to 5,000.

When orienting a rod-like liquid crystalline compound, it is preferable that an oriented film consists of a polymer which has a hydrophobic group in a side chain. The functional group type is selected according to the type of liquid crystalline molecules and the alignment state required. For example, the modification group of the modified polyvinyl alcohol may be introduced by copolymerization modification, chain transfer modification, or block polymerization modification. Examples of modified groups include hydrophilic groups (such as carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, and thiol groups), hydrocarbon groups containing 10 to 100 carbon atoms, fluoroin substituted hydrocarbon groups, Thioether groups, polymerizable groups (such as unsaturated polymerizable groups, epoxy groups, and aziridinyl groups), and alkoxyyl groups (such as trialkoxyl, dialkoxyyl, and monoalkoxyryl groups). Examples of such modified polyvinyl alcohol compounds include paragraphs [0022] to [0145] of JP 2000-155216, and paragraphs [0018] to [0022] of JP 2002-62426 ] Is disclosed.

When the alignment film is formed using a polymer having a side chain having a crosslinkable functional group bonded to the main chain or a polymer having a crosslinkable functional group in a side chain having a function of orienting liquid crystal molecules, and thereon the retardation film contains a polyfunctional monomer. When formed using the composition, it is possible to copolymerize the polymer in the alignment film and the polyfunctional monomer in the retardation film formed on the alignment film. As a result, covalent bonds are formed not only between the polyfunctional monomer molecules, but also between the polymer molecules in the alignment film and between the polyfunctional monomer and the polymer in the alignment film, so that the alignment film and the retardation film are firmly bonded. Therefore, the intensity | strength of an optical compensation film can be remarkably improved by forming an oriented film using the polymer which has a crosslinkable functional group. In this respect, it is preferable that the crosslinkable functional group of the polymer of the oriented film contains a polymerizable group as in the case of the polyfunctional monomer. Examples of such a polymerizable group include those disclosed in paragraphs [0080] to [0100] of Japanese Patent Application Laid-Open No. 2000-155216.

Apart from the crosslinkable functional group, the polymer in the oriented film can also be crosslinked using a crosslinking agent. Examples of crosslinking agents available include aldehydes, N-metholol compounds, dioxane derivatives, compounds which act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazoles, and dialdehyde starches. Two or more crosslinking agents may be used in combination. Examples of these compounds that can be used as the crosslinking agent include the compounds disclosed in paragraphs [0023] to [0024] of the specification of JP-A-2002-62426. Among these compounds, aldehydes having high reaction activity, particularly glutaraldehyde, are preferred over others.

0.1 mass%-20 mass% are preferable with respect to the polymer amount used, and, as for the addition amount of a crosslinking agent, 0.5 mass%-15 mass% are more preferable. 1.0 mass% or less is preferable and, as for ratio of the unreacted crosslinking agent which remains in an oriented film, 0.5 mass% or less is more preferable. By adjusting in this way, even if it is long-term use of an oriented film in a liquid crystal display device, or even if it is left to stand for a long time in atmosphere of high temperature, high humidity, sufficient durability without reticulation generation can be obtained.

The alignment film is basically coated on a transparent support with a layer of a composition comprising the above-mentioned polymer and crosslinking agent, comprising an alignment layer forming material, and then drying the layer by heating (to cause a crosslinking reaction therein). It can form by rubbing the dried layer. As mentioned above, the crosslinking reaction may be carried out at any time after coating on the transparent support. When using a water-soluble polymer such as polyvinyl alcohol as the alignment layer forming material, it is preferable to use a mixture of an organic solvent (for example, methanol) having an antifoaming effect and water as a solvent for the coating compound. The ratio of water to methanol is preferably 0: 100 to 99: 1 per mass, more preferably 0: 100 to 91: 9 per mass. By adjusting the mixing ratio for the foregoing range, the generation of bubbles can be prevented, so that defects on the surface of the alignment film and even the retardation layer can be significantly reduced.

Examples of suitable application methods of the oriented film include a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method, and a roll coating method. Among these coating methods, the rod coating method is particularly preferred. Moreover, as for the film thickness after drying, 0.1 micrometer-10 micrometers are preferable. Heat drying can be performed at a temperature in the range of 20 ° C to 100 ° C. In order to form sufficient crosslinking, the heating temperature is preferably in the range of 60 ° C to 100 ° C, particularly 80 ° C to 100 ° C. Drying may last from 1 minute to 36 hours, but a suitable drying time is from 1 minute to 30 minutes. In addition, it is preferable to adjust pH to the optimal value for the crosslinking agent used. When the crosslinking agent used is glutaraldehyde, it is preferable to adjust the pH in the range of pH 4.5 to pH 5.5, particularly pH 5.

It is preferable to provide an oriented film on a transparent support. The oriented film is used after the polymer film is crosslinked in the previous method. For the vertical alignment of the rod-like liquid crystal compound, it is preferable that the alignment film does not perform a rubbing treatment. Alternatively, the alignment film may be used to orientate liquid crystal compound molecules, fix the liquid crystal compound in the alignment state to form a retardation film, and then transfer only the retardation film to the polymer film (or the transparent support). have. When the rubbing treatment is required, it is appropriate to raise the degree of crosslinking of the alignment film in advance in order to prevent dust. The value obtained by subtracting the ratio (Ma / Mb) of the amount (Ma) of the crosslinking agent remaining after crosslinking with respect to the amount (Mb) of the crosslinking agent added to the coating liquid at 1, that is, (1- (Ma / Mb)) When defined as the degree of crosslinking, the degree of crosslinking is preferably from 50% to 100%, more preferably from 65% to 100%, particularly preferably from 75% to 100%.

<< air interface vertical alignment agent >>

Typically, the liquid crystalline compound has a property of being oriented in an oblique direction at the air interface side. Therefore, in order to obtain a uniform vertically aligned state, it is required to control the liquid crystal compound present on the air interface side to be vertically aligned. For this purpose, a liquid crystal coating liquid is used to form a retardation film after incorporating a compound that is ubiquitous at the air interface and that can act to align the liquid crystalline compound in the vertical direction through its exclusion volume effect or electrostatic effect. It is preferable.

As the air interfacial alignment agent, the compounds described in JP-A-2002-20363 and JP-A-2002-129162 can be used. Furthermore, paragraphs [0072] to [0075] of Japanese Patent Application No. 2002-212100, paragraphs [0037] to [0039] of Japanese Patent Application No. 2002-262239, and Japanese Patent Application No. 2003-91752 Paragraph number [0071] to [0078] of the specification, Japanese Patent Application No. 2003-119959 Paragraph number [0052] to [0054], [0065] to [0066], [0094], and Japanese patent Paragraph Nos. [0028] to [0030] in the specification of Application No. 2003-330303, and the items described in Paragraph Nos. [0087] to [0090] of the specification of Japanese Patent Application No. 2004-003804 may be appropriately applied to the present invention. In addition, by blending these compounds of the liquid crystal coating solution, the applicability is improved so that spotting or repulsion in the coated layer can be controlled.

As for the ratio of the air interface aligning agent used for the liquid-crystal coating liquid, 0.05 mass%-5 mass% are preferable. When an air interfacial alignment agent of the fluoroine containing compound type is used, it is preferable that the ratio is 1 mass% or less.

<Discotic Liquid Crystal Compound>

Discotic liquid crystal compounds are described in C. Destrade et al., Mol . Cryst . , Vol. 71, p. Benzene derivatives described in the research report of 111 (1981), C. Destrade et al., Mol . Cryst . , Vol. 122, p.141 (1985) and Physics lett . A , 78, p. 82 (1990) Truzene derivatives described in the research report, B. Kohne et al . , Angew . Chem . , Vol. 96, p. Cyclohexane derivatives described in 70 (1984), and JM Lehn et al . , J. Chem . Commun . , p. 1794 (1985) report and J. Zhang et al . , J. Am . Chem . Soc . , 116, p. 2655 (1994), including the azacroch macrocycle and the phenylacetylene macrocycle.

Typically, discotic liquid crystal compounds have a structure in which side chains (such as straight alkyl groups, alkoxy groups, or substituted benzoyloxy groups) are radially attached to their mother core at the molecular center. Preferred are compounds in which each individual molecule or self-combination of discotic liquid crystal compounds has rotational symmetry and the discotic liquid crystal compound can exhibit a finite orientation.

When the optically anisotropic layer is formed from the discotic liquid crystal compound, the compound finally contained in the optically anisotropic layer is not required to exhibit liquid crystallinity. For example, when the low molecular discotic liquid crystal compound has a group capable of reacting with heat or light, the optically anisotropic layer is formed by a compound which is converted into a high molecular compound through a polymerization reaction or a crosslinking reaction in the state of being exposed to heat or light. Can be formed. It is a common rule that a discotic liquid crystal compound loses its liquid crystallinity by being converted into a high molecular compound. Advantageously available discotic liquid crystal compounds are disclosed in Japanese Patent Laid-Open No. 8-50206. As superposition | polymerization of a discotic liquid crystalline compound, the description is given by Unexamined-Japanese-Patent No. 8-27284.

In order to fix the discotic liquid crystalline compound by polymerization, it is required to combine with the polymerizable group and the discotic core of the discotic liquid crystalline compound as a substituent. However, the direct bonding of the polymerizable group to the discotic core makes it difficult to maintain the orientation of the discotic core during the polymerization reaction. This is the case where the linking group is introduced between the discotic core and the polymerizable group. Therefore, it is appropriate that the discotic liquid crystalline compound having a polymerizable group be a compound represented by the following formula.

D (-LQ) _n

Where D is a discotic core, L is a divalent linking group, Q is a polymerizable group and n is an integer of 4 to 12.

Examples of discotic cores D are described below. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

In the above formula, the divalent linking group (L) is a divalent linking group selected from an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-, -O-, -S-, or a combination of two or more of these groups. desirable. The divalent linking group (L) is a divalent linking group formed by bonding two or more divalent linking groups selected from an alkylene group, an arylene group, -CO-, -NH-, -O-, or -S-. Among these divalent linking groups, the divalent linking group formed by defecting at least two divalent linking groups selected from an alkylene group, an arylene group, -CO-, or -O- is particularly preferred as the divalent linking group (L). The appropriate number of carbon atoms contained in each alkylene group is 1 to 12, the appropriate number of carbon atoms included in each alkenylene group is 2 to 12, and the appropriate number of carbon atoms included in each allylene group is 6 To 10.

An example of the bivalent coupler L is shown next. Each linker associates with the disscotic core (D) on the left side and the polymerizable group on the right side. AL represents an alkylene or alkenylene group, and AR represents an allylene group. In addition, the alkylene, alkenylene, and arylene groups may have a substitution (such as an alkyl group).

L1: -AL-CO-O-AL-

L2: -AL-CO-O-AL-O-

L3: -AL-CO-O-AL-O-AL-

L4: -AL-CO-O-AL-O-CO-

L5: -CO-AR-O-AL-

L6: -CO-AR-O-AL-O-

L7: -CO-AR-O-AL-O-CO-

L8: -CO-NH-AL-

L9: -NH-AL-O-

L10: -NH-AL-O-CO-

L11: -O-AL-

L12: -O-AL-O-

L13: -O-AL-O-CO-

L14: -O-AL-O-CO-NH-AL-

L15: -O-AL-S-AL-

L16: -O-CO-AR-O-AL-CO-

L17: -O-CO-AR-O-AL-O-CO-

L18: -O-CO-AR-O-AL-O-AL-O-CO-

L19: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-

L20: -S-AL-

L21: -S-AL-O-

L22: -S-AL-O-CO-

L23: -S-AL-S-AL-

L24: -S-AR-AL-

In the previous formula the polymerizable group (Q) is selected according to the type of polymerization reaction used. In particular, a polymerizable group (Q) unsaturated polymerizable group or an epoxy group is preferable, an unsaturated polymerizable group is more preferable, and an ethylenic unsaturated polymerizable group is especially preferable.

In the previous formula, n is an integer of 4 to 12. The specific number is selected according to the type of discotic core (D) used. The plurality of L-Q combinations may be the same or different but preferably the same.

As the arrangement of the liquid crystal compound molecules, the average direction of the molecular symmetry axis of the optically anisotropic layer forms an angle of 43 ° to 47 ° with respect to the longitudinal direction.

In the hybrid arrangement, the angle at which the axis of molecular symmetry of the liquid crystalline compound molecules forms with the support surface increases or decreases as the distance from the support surface in the depth direction of the optically anisotropic layer increases. However, the angle preferably decreases with increasing distance. The angle may vary in various states, such as a continuous increase state, a continuous decrease state, an intermittent increase state, an intermittent decrease state, a state including a continuous increase and a continuous decrease, and an intermittent change state including an increase and a decrease. It may change from. Intermittent changes include areas where there is no change in tilt angle at the midpoint of the thickness direction.

As long as the angle is in the increasing or decreasing state as a whole, an area without an angle change may be included, but the angle is preferably in the continuous changing state.

Typically, the average direction of the molecular symmetry axis of the liquid crystalline compound molecules can be controlled by appropriately selecting the liquid crystalline compound or material for the alignment film, or by appropriately selecting the rubbing treatment method. In the case of an optical compensation film in which the slow axis of the transparent support is not perpendicular or parallel to the slow axis of the optically anisotropic layer, the direction of the slow axis of the optically anisotropic layer can be adjusted by performing a rubbing treatment in a direction different from the slow axis of the transparent support. .

Usually, the direction of the molecular symmetry axis of the liquid crystalline compound molecules on the surface side (air side) of the optically anisotropic layer can be controlled by appropriately selecting the kind of the liquid crystalline compound or the additive used in combination with the liquid crystalline compound. Examples of additives usable in combination with liquid crystalline compounds include plasticizers, surfactants, polymerizable monomers, and polymerizable polymers. Similar to the above, the angle change in the orientation direction of the molecular symmetry axis can be controlled by appropriately selecting the kind of liquid crystal compound and the kind of additive. In the selection of the surfactant, it is desirable to ensure an adjustment with its surface tension which controls the effect of the coating liquid.

As the plasticizer, surfactant, and polymerizable monomer in which the liquid crystalline compound is used in combination, it is preferable to have compatibility with the liquid crystalline compound, to give a change in the inclination angle with respect to the liquid crystalline compound, or to have no obstacle to orientation. . Among these additives, polymerizable monomers (such as a compound having a vinyl group, a vinyloxy group, an acryloxy group, or a methacryl oil group) are preferable. 1 mass%-50 mass% are preferable, and, as for the quantity of the added compound, 5 mass%-30 mass% are more preferable. In addition, the mixing of monomers having four or more polymerizable functional groups in the additive can increase the adhesion between the alignment film and the optically anisotropic layer.

When the liquid crystalline compound used is a disocotic liquid crystalline compound, a polymer having a measure of compatibility with the discotic liquid crystalline compound and capable of changing the tilt angle of the discotic liquid crystalline compound is added to the optically anisotropic layer.

As the added polymer, cellulose esters and cellulose ethers are suitable, and cellulose esters are preferred to cellulose ethers. Examples of cellulose esters include cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. An example of a cellulose ether is hydroxypropyl cellulose. The amount of such polymer added is controlled so as not to interfere with the orientation of the discotic liquid crystalline compound molecules. In particular, the amount of the polymer added is preferably from 0.1% by mass to 10% by mass, more preferably from 0.1% by mass to 8% by mass, even more preferably from 0.1% by mass to 5% by mass, based on the discotic liquid crystalline compound.

The discotic nematic liquid crystal phase-solid phase transition temperature in the discotic liquid crystalline compound is preferably 70 ° C. to 300 ° C., and more preferably 70 ° C. to 170 ° C.

0.1 micrometer-20 micrometers are preferable, as for the thickness of an optically anisotropic layer, 0.5 micrometer-15 micrometers are more preferable, and 1 micrometer-10 micrometers are still more preferable.

<< alignment film >>

It is preferred that an oriented film is provided between the transparent support and the optically anisotropic layer.

The oriented film is preferably a layer made of a crosslinked polymer. For the formation of such layers, crosslinkable polymers can be used. For example, polymers having crosslinking functional groups are made to react with each other by applying light or heat or by changing the pH, so that crosslinking is formed. Alternatively, the polymer may be crosslinked by using a crosslinking agent. The crosslinking agent used is a highly reactive compound, and the linking group derived from the crosslinking agent is introduced between the polymers to form a crosslinking between the polymers.

Usually, an orientation film made of a crosslinked polymer may be formed by coating a layer of a coating liquid containing a crosslinked polymer or a mixture of a polymer and a crosslinking agent on a transparent support, followed by light or heat treatment or pH adjustment of the coating layer.

In order to prevent dust during the rubbing treatment of the oriented film, it is appropriate to increase the degree of crosslinking of the oriented film in advance. The value obtained by subtracting the ratio (Ma / Mb) of the amount (Ma) of the crosslinking agent remaining after crosslinking with respect to the amount (Mb) of the crosslinking agent added to the coating liquid at 1, that is, (1- (Ma / Mb)) When defined as the degree of crosslinking, the degree of crosslinking is preferably from 50% to 100%, more preferably from 65% to 100%, particularly preferably from 75% to 100%.

Examples of polymers usable for the oriented film include polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, polystyrene, polymaleimide, polyvinyl alcohol, modified polyvinyl alcohol, poly (N-methylolacrylamide), Polyvinyl toluene, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, cloned polyolefin, polyester, polyimide, polyvinyl acetate, polyethylene, carboxymethyl cellulose, gelatin, polypropylene, polycarbonate, and ( Optionally two of the aforementioned polymers), such as acrylic acid methacrylic acid copolymer, styrene-maleimide copolymer, styrene-vinyltoluene copolymer, vinyl acetate-vinyl chloride copolymer, and ethylene-vinylacetate copolymer It contains the copolymer of the monomer which comprises. Silane coupling may also be used as the polymer. As a polymer for oriented films, a water-soluble polymer is suitable.

Among these polymers, poly (N-methylolacrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferred than others, and gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are particularly preferred. And polyvinyl alcohol and modified polyvinyl alcohol are most preferred.

The saponification degree of the polyvinyl alcohol and the degree of saponification of the modified polyvinyl alcohol are preferably 70% to 100%, more preferably 80% to 100%, and even more preferably 85% to 95%. The polymerizability of the polyvinyl alcohol and the degree of polymerization of the modified polyvinyl alcohol are preferably from 100 to 3,000.

In the modification of polyvinyl alcohol, the modifying group may be introduced by any of copolymerizable modification, chain transfer modification, and block polymerizable modification. Examples of modified groups introduced by polymerizability include -COONa, -Si (OX) ₃ , wherein X is a hydrogen element or an alkyl group, -N (CH ₃ ) ₃ Cl-, -C ₉ H ₁₉ , -COO, -SO ₃ Na, and -C ₁₂ H ₂₅ . Examples of modifying groups introduced by chain transfer include -COONa, -SH, and -C ₁₂ H ₂₅ . Examples of modifying groups introduced by block polymerizability include -COOH, -CONH ₂ , -COOR (where R is an alkyl group), and -C ₆ H ₅ . In addition, the alkylthio group is a suitable modification group.

Description of the modified polyvinyl alcohol can be found in Japanese Patent Laid-Open No. 8-338913.

When a hydrophilic polymer similar to polyvinyl alcohol is used in the orientation film, the moisture content percentage is preferably controlled in view of the hardness of the film. The water content percentage is preferably 0.4% to 2.5%, more preferably 0.6% to 1.6%. The moisture content percentage can be measured with a commercial moisture percentage measuring device using Karl Fisher technology.

It is preferable that an oriented film has a thickness of 10 micrometers or less.

<Other materials of the retardation layer>

In combination with the liquid crystalline compounds as mentioned above, plasticizers, surfactants, and polymerizable monomers are used, whereby the nonuniformity of the coating layer, the layer strength and orientation of the liquid crystalline compound can be improved. These materials preferably have good compatibility with the liquid crystalline compound and do not interfere with the orientation of the liquid crystalline compound.

Examples of the polymerizable monomer include a radical polymerizable compound and a cationic polymerizable compound. Polyfunctional radically polymerizable monomers are preferred, and monomers copolymerizable with liquid crystal compounds having a polymerizable group as mentioned above are advantageously used. In particular, the compounds disclosed in paragraphs [0018] to [0020] of Japanese Patent Laid-Open No. 2002-296423 can be used. The amount of such compound added is usually 1% by mass to 50% by mass, preferably 5% by mass to 30% by mass, based on discotic liquid crystalline molecules.

Examples of surfactants include compounds so far known as surfactants, but fluorine-containing compounds are particularly preferred. More preferably, the compounds disclosed in paragraphs [0028] to [0056] of Japanese Patent Laid-Open No. 2002-330725, and paragraphs [0069] to [0126] of the specification of Japanese Patent Application No. 2003-295212 The disclosed compounds can be used to advantage.

It is preferable that the polymer used in combination with the liquid crystal compound can increase the viscosity of the coating liquid. Examples of such polymers include cellulose esters, and suitable examples of cellulose esters include the compounds disclosed in paragraph No. of Japanese Patent Laid-Open No. 2000-155216. In order not to disturb the orientation of the liquid crystal compound, it is appropriate to add the polymer to the liquid crystalline molecules at a ratio of 0.1% by mass to 10% by mass, preferably at a ratio of 0.1% by mass to 8% by mass.

In addition, the optically anisotropic layer has a Re value in the range of 0 nm to 10 nm, and its Rth value is preferably in the range of -80 nm to -400 nm.

(Manufacture of optical correction film)

Generally, optical correction films are made in the form of rolls. It is preferable to manufacture a roll optical compensation film by performing the process of following (1)-(4) continuously.

(1) Transparent feeding in the longitudinal direction by coating a layer of the resin solution, drying the layer, and performing a rubbing treatment to make the resin layer into an oriented film, or by laminating coating of a pre-formed oriented film. Forming an oriented film on the long length of the support;

(2) applying a coating liquid containing a liquid crystalline compound to the surface of the alignment film;

(3) At the same time as drying the coated coating liquid or after drying, the molecules of the liquid crystalline compound are oriented by heating the liquid crystalline compound at a temperature equal to or higher than the transition temperature of the liquid crystalline compound to fix the orientation to form an optically anisotropic layer. fair; And

(4) The process of winding the long length of the laminated product provided by the optically anisotropic layer.

In the process (3), while the liquid crystalline compound is oriented at a temperature above its transition temperature, it is preferable that the film surface wind speed of the surface of the liquid crystalline compound satisfies the following formula from a direction other than the rubbing treatment direction:

0 <V <5.0 × 10 ^-3 × η

Here, V is the film surface air velocity (m / sec) of the liquid crystalline compound surface, and (eta) is the viscosity (cp) of the optically anisotropic layer in the orientation temperature of a liquid crystalline compound.

The most suitable range of V is 0 to 2.5 × 10 ⁻³ × η.

According to the process (1)-(4), the average direction of the orthogonal projection of the molecular symmetry axis of the liquid crystalline compound molecule to the transparent support surface (average direction of the molecular symmetry axis of the optically anisotropic layer) is the in-plane slow axis of the transparent support (transparent support) It is possible to continuously and continuously manufacture an optical compensation film different from the longitudinal direction of the film), and furthermore, the angle between the average direction of the molecular symmetry axis and the rubbing direction is -2 ° to + 2 °, and -1 ° to + 1 °. Preferred, or substantially 0 °. In other words, the production method comprising (1) to (4) is suitable for mass production.

When the optical compensation film is applied to an OCB mode liquid crystal display, the angle that the average direction of the axis of molecular symmetry forms with the in-plane slow axis of the transparent support (the longitudinal direction of the transparent support) is 45 ° in a practical sense.

In the step (2), the polymerizable liquid crystal compound having a crosslinkable functional group is used as the liquid crystal compound, and in the step (3), the coating layer is continuously irradiated with light to cure the polymerizable liquid crystal compound by polymerization to give an orientation state. After fixing, the step (4) can be carried out subsequently.

Prior to step (2), a step of removing dust from the rubbing treatment surface of the transparent support or the oriented film may be performed.

Prior to step (4), an inspection step of inspecting the optically anisotropic layer formed in step (3) may be performed by continuously measuring its optical properties.

The detailed description of the process (1) to (4) is described in Unexamined-Japanese-Patent No. 9-73081.

From the viewpoint of handling suitability and web life, the diameter of the rubbing roller used in the step (1) is preferably 100 nm to 500 mm, more preferably 200 mm to 400 mm. The rubbing roller is required to have a width wider than the width of the conveyed film, and the width of the rubbing roller is preferably (film width) × 2 ^1/2 or more. It is preferable to set the rotation speed of a rubbing roller to a low value from a dust prevention viewpoint. According to the orientation of the liquid crystal compound, the rotation speed is preferably 100 rpm to 1,000 rpm, and more preferably 250 rpm to 850 rmp.

Even if the rotation speed of the rubbing roller is set to a low value, in order to maintain the orientation of the liquid crystal compound, it is preferable to heat the transparent support or the alignment film during the rubbing treatment. It is appropriate to set the heating temperature so that the surface temperature of the transparent support or the oriented film is in the range of (glass transition temperature minus 50 ° C of material) to (glass transition temperature plus 50 ° C of material). When an oriented film made of polyvinyl alcohol is used, it is suitable to control the ambient humidity during the rubbing treatment. The relative humidity at 25 ° C. is preferably 25% to 70%, more preferably 30% to 60%, particularly preferably 35% to 55%.

From the viewpoint of the productivity and the orientation of the liquid crystal, the conveyance speed of the transparent support is preferably 10 m / min to 10 m / min, more preferably 15 m / min to 80 m / min. For supply, various apparatuses used for film conveyance can be used so far. There is no restriction | limiting in particular about a conveyance system.

An oriented film can be formed by apply | coating the coating liquid which melt | dissolved materials, such as polyvinyl alcohol, in water or an organic solvent to a transparent support body, and drying. Fabrication of the oriented film can be performed prior to a series of processes. Alternatively, the oriented film may be formed continuously on the long length surface of the transparent support being conveyed.

In process (2), the coating liquid containing a liquid crystalline compound is apply | coated to the orientation film surface. As a solvent of the coating liquid, an organic solvent is preferable. Examples of such organic solvents include amides (such as N, N-dimethylformamide), sulfoxides (such as dimethyl sulfoxide), heterocyclic compounds (such as pyridine), hydrocarbons (such as benzene and toluene), Alkyl halides, such as chloroform, dichloromethane, and tetrachloroethane, esters (such as methyl acetate, butyl acetate), ketones (such as acetone, methyl ethyl ketone), and ethers (tetrahydrofuran, 1,2-dime Ethers such as methoxyethane). Of these solvents, alkyl halides and ketones are preferred over others. Two or more organic solvents may be used in combination.

In order to form a highly uniform optically anisotropic layer, the surface tension of a coating liquid is 25 mN / m or less, and 22 mN / m or less is preferable.

In order to achieve low surface tension, it is suitable to add a surfactant to the coating liquid for the optically anisotropic layer. The surfactant is preferably a fluorine-containing surfactant, more preferably a fluorine-containing polymer type surfactant, and particularly preferably a surfactant including a polymer having a fluoroaliphatic group. The fluoroine-containing polymer may be a copolymer composed of fluoroine-containing repeating units and other repeating units (eg, derivatives of polyoxyalkylene (meth) acrylates).

3,000-100,000 are preferable and, as for the mass mean molecular weight of a fluorine-containing polymer, 6,000-80,000 are more preferable. The amount of the fluorine-containing polymer added is preferably 0.005% by mass to 8% by mass, more preferably 0.01% by mass to 1% by mass, and more preferably 0.05% by mass to 0.5, based on the solids of the coating liquid containing the liquid crystalline compound as a main component. Mass% is particularly preferred.

Applying the coating liquid to the oriented film surface can be carried out using any of the known methods (such as wire bar coating method, extrusion coating method, direct grabber coating method, reverse grabber coating method, and die coating method). have.

In the step (3), the liquid crystalline compound molecules are oriented at or above the transition temperature at the same time as or after the drying of the applied coating liquid, and the orientation state is fixed, resulting in the formation of an optically anisotropic layer. During or after the heat drying, the liquid crystalline compound is oriented as desired. The drying temperature can be determined in consideration of the boiling point of the material used for the transparent support and the alignment film and the solution used for the coating liquid. The orientation temperature can be determined based on the liquid crystal phase-solid phase transition temperature of the liquid crystal compound used. When the liquid crystalline compound used is a discotic liquid crystalline compound, the orientation temperature is preferably selected in the range of 70 ° C to 300 ° C, more preferably in the range of 70 ° C to 170 ° C.

10 cp-10,000 cp are preferable and, as for the viscosity of a liquid crystalline state, 100 cp-1,000 cp are more preferable. When the viscosity is too low, it is susceptible to wind blowing during orientation, and very high wind speed / wind control is required for continuous production. On the other hand, when the viscosity is high, the liquid crystalline molecules are less susceptible to wind, but their orientation is slowed down and productivity is very poor.

The viscosity of the liquid crystal layer can be controlled by the molecular structure given to the liquid crystalline compound. In addition, the viscosity can be adjusted by using an appropriate amount of an additive (particularly, a cellulose polymer) and a gelling agent of the optically anisotropic layer.

The heating can be performed by blowing hot air at a predetermined temperature or by passing a heated room maintained at the predetermined temperature.

The optically anisotropic layer is formed by fixing the aligned liquid crystal compound while maintaining the alignment state. Fixation of a liquid crystalline compound can be performed by cooling to solid phase transition temperature, or by a polymerization reaction. It is preferable to fix by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Photopolymerization reaction is preferred. Examples of photopolymerization initiators include α-carbonyl compounds (as disclosed in US Pat. No. 2,367,661, US Pat. No. 2,357,670), acyloin ether (as disclosed in US Pat. No. 2,448,828), (as disclosed in US Pat. No. 2,722,512). α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds (as disclosed in US Pat. No. 3,046,127, US Pat. No. 2,951,758), and triarylimidazole dimers (as disclosed in US Pat. No. 3,549,367). Combinations with aminophenyl ketones, acridine and phenazine compounds (disclosed in JP-A-60-105667, US Pat. No. 4,239,850), and oxadiazole compounds (disclosed in US Pat. No. 4,212,970) . 0.01 mass%-20 mass% of solid content of a coating liquid are preferable, and, as for the usage-amount of a photoinitiator, 0.5 mass%-5 mass% are more preferable.

It is preferable to use ultraviolet-ray for the light irradiation for advancing superposition | polymerization of a liquid crystalline compound and fixing the orientation state. The irradiation energy is preferably in the range of 20 mJ / cm ² to 50 J / cm ² , and more preferably in the range of 100 mJ / cm ² to 800 mJ / cm ² . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. Light irradiation can be performed by passing the transparent support body coated with the coating liquid of an optically anisotropic layer along the conveyance path in which the light source was arrange | positioned up and down or left and right.

Before proceeding to the step (4), a protective layer can be provided on the optically anisotropic layer formed in the step (3). For example, the protective film prepared previously can also be laminated | stacked continuously on the surface of the optically anisotropic layer manufactured by long length.

In step (4), the long length of the laminated article provided with the optically anisotropic layer is wound with a roll. For example, the continuously conveyed support body which has an optically anisotropic layer can be wound up to a cylindrical core.

The optical compensation film obtained in the step (4) has a roll form, and its handling is easy when the film is produced in large quantities. In addition, the shape can be stored and returned.

(Polarizing plate)

The polarizing plate includes two transparent protective films and polarizers arranged at both ends thereof. As one protective film, the cellulose acylate film of the present invention can be used. As another protective film, a normal cellulose acylate film can also be used. The polarizer includes an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. Iodine based polarizers and dye based polarizers are generally produced using polyvinyl alcohol based films. When using the cellulose acylate film of this invention as a protective film for polarizers, the manufacturing method of a polarizing plate is not specifically limited, It can manufacture by a general method. In the polarizing plate manufacturing method, the optical compensation film thus obtained is subjected to an alkali treatment, the polyvinyl alcohol film is immersed in an iodine solution, and bonded to both ends of the prepared polarizer using an aqueous solution of fully saponified polyvinyl alcohol, followed by stretching. Steps. Instead of alkali treatment, a process for facilitating adhesion may be used as described in Japanese Patent Application Laid-open No. Hei 6-94915 and Japanese Patent Application Laid-open No. Hei 6-118232. Adhesives used to bond the treated surface of the protective film to the polarizer include, for example, polyvinyl alcohol based adhesives such as polyvinyl alcohol and polyvinyl butyral, and vinyl latexes such as butyl acrylate. Typically, the polarizing plate includes a polarizer and a protective film protecting both sides of the polarizer, and further includes a protective film attached to one surface of the polarizing plate and a separate film attached to the rear surface thereof. Protective films and separate films are used to protect the polarizers during shipment of the polarizers and inspection of their products. In this case, a protective film is attached to protect the surface of the polarizing plate, and the polarizing plate is used on the back side of the surface to be attached to the liquid crystal plate. The separate film is used to cover the adhesive layer to be attached to the liquid crystal plate and the polarizing plate is used on the side of the surface to be attached to the liquid crystal plate.

It is preferable that the cellulose acylate film of the present invention is attached to the polarizer so that the slow axis of the cellulose acylate film of the present invention coincides with the transmission axis of the polarizer. Evaluation of the polarizer prepared under polarizer cross nicol is the polarization degree under polarizer cross nicol when the orthogonal precision between the slow axis of the cellulose acylate film of this invention and the absorption axis (axis orthogonal to a transmission axis) of a polarizer is larger than 1 degree. Degraded, indicating that light is missing. In this case, when combined with the liquid crystal cell, sufficient black level or contrast cannot be obtained. Therefore, 1 degree or less is preferable and, as for the deflection between the direction of the main refractive index nx of the cellulose acylate film of this invention, and the direction of the transmission axis of a polarizer, 0.5 degrees or less are more preferable.

In the polarizing plate of the present invention, the single plate transmittance (TT), parallel transmittance (PT), orthogonal transmittance (CT), and polarization degree (P) are at least one of the following formulas (a) to (d) at 25 ° C and 60% RH. It is desirable to satisfy.

         40.0≤TT≤45.0 (a)

         30.0≤PT≤40.0 (b)

         CT≤2.0 (c)

         95.0≤P (d)

Single plate transmittance (TT), parallel transmittance (PT), and orthogonal transmittance (CT) are respectively in this order, more preferably 40.5≤TT≤45, 32≤PT≤39.5, CT≤1.5, still more preferably 41.0≤ TT≤44.5, 34≤PT≤39.0, CT≤1.3. 95.0% or more of polarization degree P is preferable, More preferably, it is 96.0% or more, More preferably, it is 97.0% or more.

When the polarizing plate of this invention makes the orthogonal transmittance to the wavelength of (lambda) into CT ((lambda)), CT ₍₃₈₀₎ , CT ₍₄₁₀₎ , CT ₍₇₀₀₎ is one or more of following formula (e)-(g) It is desirable to be satisfied.

CT ₍₃₈₀₎ ≤2.0 (e)

CT ₍₄₁₀₎ ≤1.0 (f)

CT ₍₇₀₀₎ ≤0.5 (g)

More preferably, CT ₃₈₀ ≤ 1.95, CT ₄₁₀ ≤ 0.9, CT ₇₀₀ ≤ 0.49, still more preferably CT ₃₈₀ ≤ 1.90, CT ₄₁₀ ≤ 0.8, and CT _{700 )} it is ≤0.48.

In the polarizing plate of the present invention, when the polarizing plate is placed under conditions of 60 ° C. and 95% RH for 500 hours, the amount of change in orthogonal single plate transmittance (ㅿ CT) and the amount of change in polarization degree (ㅿ P) are represented by the following formulas (j) and (k) Meets one or more of the following:

 -6.0≤ ㅿ CT≤6.0 (j)

       -10.0≤ ㅿ P≤0.0 (k)

Here, the change amount represents the value obtained by subtracting the measured value before the test from the measured value after the test.

More preferably, it is -5.8 <= CT <= 5.8, and -9.5 <= P <0.05, More preferably, it is -5.6 <= CT <= 5.6 and -9.0 <= P <= 0.

In the polarizing plate of the present invention, when the polarizing plate is placed under conditions of 60 ° C. and 90% RH for 500 hours, the amount of change in the orthogonal single plate transmittance (ㅿ CT) and the amount of change in the degree of polarization (ㅿ P) are represented by the following formulas (h) and (i) Meets one or more of the following:

 -3.0≤ ㅿ CT≤3.0 (h)

 -5.0≤ ㅿ P≤0.0 (i)

When the polarizing plate is placed under conditions of 80 ° C. for 500 hours, the amount of change in the orthogonal single plate transmittance (ㅿ CT) and the amount of change in the degree of polarization (ㅿ P) satisfy at least one of the following formulas (1) and (m).

 -3.0≤ ㅿ CT≤3.0 (l)

 -2.0≤ ㅿ P≤0.0 (m)

Single plate transmittance (TT), parallel transmittance (PT), and orthogonal transmittance (CT) of the polarizing plate were measured in the range of 380 nm to 780 nm using UV3100PC (manufactured by Shimadzu Corporation). Average values (average values from 400 nm to 700 nm) are used. The polarization degree P can be obtained by polarization degree (%) = 100 x [(parallel transmittance-orthogonal transmittance) / (parallel transmittance + orthogonal transmittance)] ^1/2 . The polarizer durability test is carried out in two types, (1) polarizer only and (2) polarizer attached to glass with an adhesive. In the measurement of the form of a polarizing plate only, two cellulose acylate films of this invention are sandwiched and combined between two polarizers, and the same thing is prepared and measured. In the glass adhesion state, two samples (about 5 cm x 5 cm) with a polarizing plate adhered on the glass are prepared so that the cellulose acylate film of the present invention is disposed on the glass side. In the measurement of single plate transmittance, the film side of this sample is measured by setting it toward the light source. Two samples are respectively measured and the average value from it is made into single plate transmittance.

(Moistureproof envelope)

In the present invention, the "moisture-proof bag" is defined by the moisture permeability measured based on the cup method (JIS-Z208). In consideration of the influence of environmental humidity on the outside of the bag, it is preferable to use a material having a water vapor transmission rate of 30% / (m ² · Day) at 40 ° C. or less. 30 g / (m ² · Day) cannot prevent the influence of environmental humidity outside the envelope. WVTR is 1Og / (m ² · Day) or less and, more ^{preferably, 5g / (m 2 · Day} ) or less is most preferred.

The material of the moisture-proof bag is not particularly limited as long as it satisfies the above-mentioned moisture permeability, and known materials may be used (Hoso Zairyo Binran (Manual of packaging Materials), Japan Packaging Institute (1995), Hoso Zairyo no Kiso Chisiki). (Basic Knowledge of Packaging Materials), Japan Packaging Institute (Nov. 2001), Kinosei Hoso Nyumon (Introduction to Functional Packaging), 21st Century Packaging Research Institute (February 28, 2002, first edition, first printed) In the present invention, a material having low moisture permeability, light weight, and easy handling is preferable, and a composite material such as a vapor deposition film obtained by depositing silica, alumina, ceramic material, etc. on a plastic film, or a laminated film of plastic film and aluminum foil. As the thickness of the foil, a special agent having a thickness such that the foil has a thickness such that the humidity of the bag is not affected by the environmental humidity. However, the thickness of the foil is preferably several micrometers to several hundred micrometers, and particularly preferably several micrometers to 500 micrometers The humidity of the moisture-proof bag for use in the present invention satisfies any one of the followings. desirable.

When the polarizing plate is packaged, it is required to adjust the humidity of the package in a range of 43% RH to 70% RH at a temperature of 25 ° C, more preferably 45% RH to 65% RH, more preferably 45 % RH to 63% RH are required.

Humidity of the bag in which the polarizing plate is packaged is required to be adjusted so as to be different from the ambient humidity by 15% RH or less by laminating the polarizing plate on the liquid crystal panel.

(Reflective layer)

It is preferable to provide a functional film such as an antireflection layer on the transparent protective film disposed on the opposite side of the liquid crystal cell of the polarizing plate. In particular, in the present invention, an antireflection layer in which at least a light scattering layer and a low refractive index layer are laminated in this order on a transparent protective film or an antireflection layer in which a high refractive index layer and a low refractive index layer are laminated in this order on a transparent protective film is used. It is appropriate. Preferred examples thereof are described below.

Preferred examples of the antireflection layer provided with the light scattering layer and the low refractive index layer on the transparent protective film are described.

Matt particles dispersed in the light scattering layer used in the present invention are dispersed, the refractive index of the material of the light scattering layer except the matt particles is preferably in the range of 1.50 to 2.00, the refractive index of the low refractive index layer is in the range of 1.35 to 1.49 desirable. In the present invention, the light scattering layer has both anti-glare properties and hard coat properties, and may constitute one layer or a plurality of layers, for example, two to four layers.

The surface irregularities of the antireflection layer have a centerline average roughness (Ra) of 0.08 μm to 0.40 μm, a 10-point average roughness (Rz) of 10 times or more of Ra, and an average concave-convex distance (Sm) of 1 μm to 100 Μm, the standard deviation of the convex height from the deepest part of the concave and convex is 0.5 μm or less, the standard deviation of the average concave-convex distance Sm based on the center line is 20 μm or less, and the inclination angle is 0 to 5 degrees. By designing to provide 10% or more of the cotton, it is preferable because sufficient anti-glare properties and a uniform matte structure in the naked eye can be achieved. In the color of the reflected light under the C light source, the a * value is -2 to 2, the b * value is -3 to 3, and the ratio of the minimum value and the maximum value of the reflectance within the range of 380 nm to 780 nm is 0.5 to 0.99, It is desirable for the color to be neutral. Furthermore, by adjusting the b * value of the transmitted light under the C light source to 0 to 3, it is desirable to reduce the yellowish color of the white display when applied to the display device. Furthermore, when the luminance distribution was measured on the film by inserting a 120 μm × 40 μm grating between the surface light source and the antireflective film, the standard deviation was 20 or less, and the glare was reduced when the film of the present invention was applied to a high-precision panel. Is preferred.

When the antireflective layer used in the present invention is an optical characteristic having a mirror reflectance of 2.5% or less, a transmittance of 90% or more, and a 60 degree gloss value of 70% or less, reflection of external light can be suppressed, and visibility is improved. Therefore, such an anti-glare layer is preferable. In particular, the mirror reflectance is more preferably 1% or less and most preferably 0.5% or less. Haze 20% to 50%, internal haze / total haze value 0.3 to 1, haze value after formation of low refractive index layer from haze value to light scattering layer is 15% or less, transmission image clarity at 0.5 mm comb width Has a transmittance ratio of 20% to 50% and a transmittance ratio of 1.5 to 5.0 in a direction inclined at 2 degrees in the vertical transmission light / vertical direction, to prevent glare on a high-precision LCD panel and to reduce blurring of characters and the like. Therefore, this is preferable.

(Low refractive index layer)

The refractive index of the low refractive index layer of the antireflective film used in the present invention is 1.20 to 1.49, preferably in the range of 1.30 to 1.44. Since the reflectance decreases, it is preferable that the refractive index of the low refractive index layer satisfies the following formula (i).

(m / 4) × 0.7 <n1d1 <(m / 4) × 1.3 (Ⅸ)

Where m is a positive odd number, n1 is the refractive index of the low refractive index layer, and d1 is the thickness (nm) of the low refractive index layer. λ is the wavelength and is a value in the range of 500 nm to 550 nm.

The material for forming the low refractive index layer used in the present invention is described below.

The low refractive index layer used in the present invention contains a fluorine-containing polymer as the low refractive index binder. The fluorine-containing polymer is preferably a fluorine-containing polymer capable of crosslinking by heat or ionizing radiation having a coefficient of dynamic friction of 0.03 to 0.20, a contact angle of water of 90 ° to 120 °, and a slide-down angle of pure water of 70 ° or less. Do. When the antiglare film used in the present invention is attached to the image display device, if the peeling force from a commercially available adhesive tape is low, the seal or memo adhered thereon is easily peeled off. The peeling force is preferably 500 gf or less, more preferably 300 gf or less, and most preferably 100 gf or less. The higher the surface hardness measured by the microhardness meter, the less likely it is to scratch the film. 0.3 GPa or more is preferable and, as for the surface hardness of a film, 0.5 GPa or more is more preferable.

As a fluorine-containing polymer used for the low refractive index layer, hydrolysis and dehydration of a perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane) In addition to condensation, the fluorine-containing copolymer containing a fluorine-containing monomer unit and the structural unit for providing crosslinking reactivity is included.

Specific examples of the fluorine-containing monomer unit include fluoroolefins (for example, fluoroethylene, vinylidene, fluoride, tetrafluoroethylene, perfluorooctylethylene, hexafluoropropylene, or perfluoro-2 , 2-dimethyl-1,3-diosol), partially or fully fluorinated alkyl ester derivatives of (meth) acrylic acid (e.g., Biscoat 6FM (manufactured by Osaka Organic Chemical Industry, Ltd.) or M-2020 (Daikin Industries, Ltd.)), and fully or partially fluorinated vinyl ethers. Preferably it is a perfluoroolefin, Especially preferably, it is hexafluoropropylene from a viewpoint of refractive index, solubility, transparency, and solubility.

Structural units for imparting crosslinking reactivity include structural units, carboxyl groups, hydroxy groups, amino groups, which can be obtained by polymerization of monomers having a self-crosslinking functional group in a molecule, such as glycidyl (meth) acrylate or glycidyl vinyl ether. Or a monomer having a sulfo group (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxy ethyl vinyl ether, hydroxy butyl vinyl ether, male) A structural unit obtained by introducing a crosslinkable group such as a (meth) acryloyl group by a polymer reaction into the structural unit obtained by polymerization of an acid or crotonic acid, or the structural unit mentioned above (for example, the crosslinkable group is a hydroxy group). By a technique for reacting acryloyl chloride).

In addition to the above-mentioned fluorine-containing monomer units and structural units for imparting crosslinking reactivity, monomers containing no fluorine atom can be copolymerized appropriately from the viewpoint of solubility in a solvent and transparency of the film. The monomer units usable at the same time are not particularly limited, and examples thereof include olefins (such as ethylene, propylene, isoprene, vinyl chloride, or vinylidene chloride), olefins (methyl acrylate, ethyl acrylate, or 2-ethyl hexyl acrylate). Such as acrylic acid ester, methacrylic acid ester (such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, or ethylene glycol dimethacrylate), (styrene, divinylbenzene, vinyltoluene, or α-methylstyrene Styrene derivatives (such as methyl vinyl ether, ethyl vinyl ether, or cyclohexyl vinyl ether), vinyl esters (such as vinyl acetate, vinyl propionate, or vinyl cinnamate), and (N-tert- Acrylamide, such as butylacrylamide or N-cyclohexylacrylamide, methacrylamide, and arc And a casting reel Ronnie derivative.

The curing agent may be used in appropriate combination with the above-mentioned polymer as described in Japanese Patent Application Laid-open No. Hei 10-25388 and Japanese Patent Application Laid-open No. Hei 10-147739.

(Light scattering layer)

The light scattering layer is formed to impart a hard coat property to the film to improve light diffusivity and scratch resistance of the film by surface scattering and / or internal scattering. Therefore, a light scattering layer is formed including a binder for imparting hard coat properties, mat particles for imparting light diffusivity, and an inorganic filler for increasing refractive index, preventing crosslinking shrinkage, and increasing strength, as necessary.

In order to impart hard coat properties, the film thickness of the light scattering layer is preferably 1 µm to 10 µm, more preferably 1.2 µm to 6 µm. If the thickness is too thin, the hard coat characteristic becomes insufficient. On the other hand, if the thickness is too thick, the warpage or brittleness tends to be lowered, resulting in insufficient processing.

The binder of the scattering layer is preferably a polymer having a saturated hydrocarbon chain or a polyether chain as the main chain, and more preferably a polymer having a saturated hydrocarbon chain as the main chain. Moreover, the binder polymer preferably has a crosslinked structure. The binder having a saturated hydrocarbon chain as the main chain is preferably a polymer of ethylenically unsaturated monomer. The binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure is preferably a (co) polymer of a monomer having two or more ethylenically unsaturated groups. Further, in order to increase the refractive index, a monomer containing at least one atom selected from an aromatic ring or a halogen atom, sulfur atom, phosphorus atom, and nitrogen atom other than futso may be selected.

Monomers having two or more ethylenically unsaturated groups include polyhydric alcohols and (meth) acrylic acids (eg, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, 1,4 -Cyclohexane diacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethinol propane tri (meth) acrylate, triethylolethane tri (meth) acrylate, di Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexane Tetramethacrylate, polyurethane polyacrylate, or polyester polyacrylate), ethylene oxide modified compounds, vinylbenzenes and derivatives thereof (e.g. , 1,4-divinylcyclohexanone), vinyl sulfone (eg divinylsulphone), acrylamide (eg methylenebisacrylamide), and methacrylamide. The monomers mentioned above may be used in combination of two or more.

Specific examples of the high refractive index monomers include bis (4-methacryloylthiophenyl) sulfide, vinylnaphthalene, vinylphenylsulfide, and 4-methacryloxyphenyl1-4'-methoxyphenyl thioether. These monomers can also be used in combination of 2 or more.

Polymerization of the monomer containing these ethylenically unsaturated groups can be performed by irradiation of ionizing radiation or heating in the presence of a radical radical initiator or a thermal radical initiator.

Therefore, the coating liquid containing the monomer which has an ethylenically unsaturated group, an optical radical initiator, or a thermal radical initiator is prepared and apply | coated on a transparent support body. Thereafter, it can be cured by a polymerization reaction using ionizing radiation or heat to form an antireflection film. These photo radical initiators etc. can use a well-known thing.

The polymer having a polyether as the main chain is preferably a ring-opening polymer of a polyfunctional epoxy compound. The ring-opening polymerization of the polyfunctional epoxy compound can be carried out by irradiation of ionizing radiation or heating in the presence of an optical radical initiator or a thermal radical initiator. Therefore, the coating liquid containing a polyfunctional epoxy compound, an optical radical initiator, or a thermal radical initiator, mat particle | grains, and an inorganic filler is prepared and apply | coated on a transparent support body. Thereafter, it may be cured by a polymerization reaction by ionizing radiation or heat to form an antireflection film.

Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a monomer having a crosslinkable functional group may be used to introduce a crosslinkable functional group into the polymer, and a crosslinked structure may be introduced into the binder polymer by the reaction of the crosslinkable functional group.

Examples of the crosslinkable functional group include an isocyanate group, an epoxy group, an aziridine group, an oxazoline group, an aldehyde group, a carbonyl group, a hydrazine group, a carboxyl group, a methylol group, and an active methylene group. Metal alkoxides such as vinyl sulfonic acid, acid anhydride, cyanoacrylate derivatives, melamine, etherified methylol, esters, urethanes, and tetramethoxysilanes can also be used as monomers for introducing a crosslinked structure. Like block isocyanate groups, functional groups exhibiting crosslinkability as a result of decomposition reactions may be used. That is, in the present invention, the crosslinkable functional group may be a group which does not immediately react but exhibits reactivity as a result of decomposition.

The binder polymer which has these crosslinkable functional groups can form a crosslinked structure by heating after coating.

The light scattering layer is larger than the filler particles for the purpose of imparting antiglare properties, and includes matt particles, for example, inorganic compound particles or resin particles, having an average particle size of 1 μm to 10 μm, preferably 1.5 μm to 7.0 μm. do.

Preferred specific examples of the above-mentioned mat particles include, for example, particles of inorganic compounds such as silica particles, TiO ₂ particles; And resin particles such as acrylic resin particles, crosslinked acrylic resin particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles. Among these, crosslinked styrene particles, crosslinked acrylic particles, crosslinked acrylic styrene resin particles, and silica particles are preferable.

The shape of the available particles may be either spherical or indeterminate.

Moreover, two or more kinds of mat particles having different particle sizes may be used in combination. Matte particles with a larger particle size can impart antiglare properties, and matte particles with a smaller particle size can impart other optical properties.

Moreover, the particle size distribution of the matt particles mentioned above is monodisperse, and each particle is preferably as similar as possible to the particle size. For example, when a particle having a particle size of 20% or more than the average particle size is defined as coarse particles, the ratio of the coarse particles is preferably 1% or less of the total particle number, more preferably 0.1. It is% or less, More preferably, it is 0.01% or less. Mat particles having such a particle size distribution are obtained by classification after a normal synthetic reaction, and mat particles having a more preferable distribution can be obtained by increasing the number of classifications or enhancing the degree thereof.

The above-mentioned mat particles are preferably such that the amount of the matt particles of the formed light scattering layer is 10 mg / m ² to 1000 mg / m ² , more preferably 100 mg / m ² to 700 mg / m ^2. It is included in the light scattering layer.

The particle size distribution of the mat particles is measured by the Coulter counter method, and the measured distribution is converted to the particle number distribution.

In order to increase the refractive index of the layer, the light scattering layer is selected from titanium, zirconium, aluminum, indium, zinc, tin, tin, and antimony, in addition to the above-mentioned matt particles, and has an average particle size of 0.2 μm. Hereinafter, it is preferable to contain the inorganic filler which is preferably 0.1 micrometer or less, More preferably, it is 0.06 micrometer or less.

In contrast, in order to increase the refractive index difference with the matte particles, it is also preferable to use an oxide of silicon in the light scattering layer using the high refractive index particles to keep the refractive index of the layer lower. Preferred particle sizes are the same as those of the inorganic fillers described above.

Specific examples of the inorganic filler used in the light scattering layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO, and SiO ₂ . TiO ₂ and ZrO ₂ are particularly preferred in terms of increasing the refractive index. The surface of the inorganic filler is preferably silane coupling treatment or titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder type on the filler surface is preferably used.

The amount of the addition of these inorganic fillers is preferably 10% to 90%, more preferably 20% to 80%, and particularly preferably 30% to 75% of the total mass of the light scattering layer.

Since these fillers have a sufficiently small particle size compared to the wavelength of light, scattering does not occur, and the dispersion in which the filler is dispersed in the binder polymer acts as an optically uniform material.

The refractive index of the bulk of the mixture of the binder of the light scattering layer and the inorganic filler is preferably 1.48 to 2.00, more preferably 1.50 to 1.80. In order to adjust a refractive index within the said range, you may select suitably the kind and quantity ratio of a binder and an inorganic filler. The method of selecting them can be easily understood experimentally in advance.

In the light scattering layer, in order to ensure surface uniformity such as coating unevenness, dry unevenness, and point defects, either or both of a fluorine-containing surfactant and a silicone-based surfactant are contained in the coating composition for forming the antiglare layer. In particular, fluorine-based surfactants are preferably used, since the addition of a smaller amount thereof has an effect of improving surface defects such as coating stains, dry stains, and point defects. It is an object to increase productivity by giving a high-speed coating tendency while increasing surface uniformity.

The antireflection layer in which the middle refractive index layer, the high refractive index layer, and the low refractive index layer are laminated in this order on the transparent protective film will be described below.

An antireflection film having a layer structure of at least a medium refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) on the substrate in this order is designed to have a refractive index that satisfies the following relationship.

Refractive Index of the High Refractive Index Layer> Refractive Index of the Medium Refractive Index Layer> Refractive Index of the Transparent Support> Refractive Index of the Low Curvature Layer

Moreover, a hard coat layer may be provided between the transparent support and the medium refractive index layer. Moreover, the antireflective layer may comprise a medium refractive index hard coat layer, a high refractive index layer, and a low refractive index layer. Examples include Japanese Patent Application Laid-Open No. 8-122504, Japanese Patent Application Laid-Open No. 8-110401, Japanese Patent Application Laid-Open No. 10-300902, Japanese Patent Application Laid-Open No. 2002-243906, Japanese Patent Application Laid-Open No. 2000 -111706.

In addition, other functions may be imparted to each layer, for example, an antifouling low refractive index layer and an antistatic high refractive index layer (for example, Japanese Patent Application Laid-Open No. 10-206603, Japanese Patent Application Laid-Open No. 2002-243906). H).

5% or less is preferable and, as for the haze of an antireflection film, 3% or less is more preferable. Moreover, as for the intensity | strength of the film measured by the pencil hardness test according to JIS K5400, H or more is preferable, 2H or more is more preferable, 3H or more is the most preferable.

(High refractive index layer and medium refractive index layer)

The layer having a high refractive index of the antireflective film is composed of a curable film containing at least an average particle size of 100 nm, an ultrafine inorganic compound particle having a high refractive index, and a matrix binder.

The ultrafine inorganic compound particles having a high refractive index include an inorganic compound having a refractive index of at least 1.65, and preferably an inorganic compound having a refractive index of at least 1.9. For example, oxides of Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms.

Such ultra-fine particles can be used for surface treatment of a particle surface (for example, Japanese Patent Application Laid-Open No. 11-295503, Japanese Patent Application Laid-Open No. 11-153703, and Japanese Patent Application Laid-Open No. 2000-9908, an anionic compound). Or Japanese Patent Application Laid-Open No. 2001-310432 relating to an organometallic coupling agent, formation of a core shell structure based on high refractive index particles (Japanese Patent Laid-Open Publication No. 2001-166104), and the use of a specific dispersant in combination. (See Japanese Patent Laid-Open No. 11-153703, US Patent No. 6,210,858, and Japanese Patent Laid-Open No. 2002-2776069).

Materials for forming the matrix include conventionally known thermoplastic resins and curable resin films.

Moreover, at least one composition selected from a polyfunctional compound-containing composition having at least two radical polymerizable groups and / or cationic polymerizable groups, a hydrolyzable group-containing organometallic compound, and partial condensates thereof is preferable. Examples include the compositions described in Japanese Patent Laid-Open No. 2000-47004, Japanese Patent Laid-Open No. 2001-315242, Japanese Patent Laid-Open No. 2001-31871, and Japanese Patent Laid-Open No. 2001-296401.

Moreover, the curable film obtained from the colloidal metal oxide and metal alkoxide composition obtained from the hydrolysis-condensation product of a metal alkoxide is also preferable. These are described, for example in Japanese Unexamined Patent Publication No. 2001-293818.

The refractive index of the high refractive index layer is generally 1.70 to 2.20. 5 nm-10 micrometers are preferable, and, as for the thickness of a high refractive index layer, 10 nm-1 micrometer are more preferable.

The refractive index of the medium refractive index layer is adjusted to a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the medium refractive index layer is preferably 1.50 to 1.70. Moreover, the thickness is preferably 5 nm to 10 m, and more preferably 10 nm to 1 m.

(Low refractive index layer)

The low refractive index layer is sequentially stacked on the high refractive index layer. The refractive index of the low refractive index layer is 1.20 to 1.55, preferably 1.30 to 1.50.

The low refractive index layer is preferably configured as an outer layer having scratch resistance and antifouling property. As a means of greatly improving scratch resistance, it is efficient to impart sliding characteristics to the surface, and means using a conventionally known silicon introduction or fluorine introduction thin film can be applied.

Furthermore, the refractive index of the fluorine-containing compound is preferably 1.35 to 1.50, more preferably 1.36 to 1.47. Moreover, the fluorine-containing compound preferably contains a fluorine atom in the range of 35% by mass to 80% by mass and contains a crosslinkable or polymerizable functional group.

The fluorine-containing compound is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-222503, paragraphs [0018] to [0026], and Japanese Patent Application Laid-Open No. 11-38202, paragraphs [0019] to [0030] It includes the compound of Unexamined-Japanese-Patent No. 2001-40284 specification paragraph No. 0027-0028, and Unexamined-Japanese-Patent No. 2000-284102.

The silicone compound is a compound having a polysiloxane structure, preferably a compound containing a curable functional group or a polymerizable functional group in the polymer chain to form a crosslinkable structure in the film. Examples include reactive silicones (e.g., silaplan (manufactured by Chisso Corporation), polysiloxanes having silanol groups at both ends thereof (Japanese Patent Laid-Open No. 11-258403)).

Fluorine-containing and / or crosslinked or polymerizable groups having a crosslinkable or polymerizable group have a coating composition for forming the outermost layer containing a polymerization initiator, a sensitizer, or the like simultaneously with or after the coating of the coating composition. It is preferable to carry out by doing this.

Furthermore, a sol gel cured film obtained by curing an organometallic compound such as a silane coupling agent and a specific fluorine-containing hydrocarbon group-containing silane coupling agent by condensation reaction in the presence of a catalyst is also preferable.

Examples thereof include a polyfluoroalkyl group-containing silane compound or a partially hydrolyzed condensate thereof (JP-A-58-142958, JP-A-58-147483, JP-A-58-147484, JP-A Japanese Patent Application Laid-Open No. 9-157582, Japanese Patent Application Laid-Open No. 11-106704, and a fluorine-containing long chain group-containing or perfluoroalkyl ether group-containing silyl group (Japanese Patent Laid-Open No. 2000-117902, Japanese Unexamined Patent Publication No. 2001-48590 and Japanese Unexamined Patent Publication No. 2002-53804).

The low refractive index layer is a low additive having an average primary particle size of 1 nm to 150 nm, such as filler (for example, silicon dioxide (silica), fluorine-containing particles (magnesium fluorine, calcium fluorine, or barium fluorine) as an additive other than the above. Refractive index inorganic compounds, or JP-A-11-3820, the organic fine particles described in paragraph Nos. [0020] to [0038]), a silane coupling agent, a sliding agent, a surfactant, and the like.

When the low refractive index layer is located below the outermost layer, the low refractive index layer may be formed by a vapor phase method (vacuum vapor deposition method, sputtering method, ion plating method, plasma CVD method, or the like). The coating method is preferable at the point that low refractive index can be manufactured at low cost.

30 nm-200 nm are preferable, as for the film thickness of a low refractive index layer, 50 nm-150 nm are more preferable, and 60 nm-120 nm are the most preferable.

(Layers other than the antireflection layer)

Furthermore, a hard coat layer, a forward scattering layer, a primer layer, an antistatic layer, an undercoat layer, a protective layer and the like may be provided.

(Hard coat layer)

The hard coat layer is provided on the surface of the transparent support to impart physical strength to the transparent protective film having the antireflective layer. In particular, it is preferred to be provided between the transparent support and the above-mentioned high refractive index layer. It is preferable that a hard-coat layer is formed by the crosslinking reaction or polymerization reaction of a light and / or a thermosetting compound. The curable functional group is preferably a photopolymerizable functional group and an organometallic compound containing a hydrolyzable functional group, particularly preferably an organic alkoxysilyl compound.

Specific examples of these compounds preferably include compounds similar to those exemplified in the high refractive index layer. Specific constituent compositions of the hard coat layer include, for example, those described in Japanese Patent Application Laid-Open No. 2002-144913, Japanese Patent Application Laid-Open No. 2000-9908, and International Publication No. 00/46617.

The high refractive index layer can serve as a hard coat layer. In such a case, it is desirable to finely disperse the fine particles using the technique described for the high refractive index layer and to allow it to be contained in the hard coat layer to form it.

In addition, the hard coat layer may serve as an antiglare layer (to be described later) that allows the inclusion of particles having an average particle size of 0.2 μm to 10 μm to impart antiglare properties.

The thickness of the hard coat layer can be appropriately designed by its use. The thickness of the hard coat layer is preferably 0.2 µm to 10 µm, more preferably 0.5 µm to 7 µm.

The strength of the hard coat layer is determined by a pencil hardness test according to JIS K5400, preferably at least H, more preferably at least 2H, and most preferably at least 3H. Furthermore, in the Taber test according to JIS K540O, it is preferable that the wear of the test piece after the test is as small as possible.

(Antistatic layer)

When an antistatic layer is provided, it is desirable to impart conductivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less in volume resistance. It is possible to impart a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ) by the use of hygroscopic substances, water soluble inorganic salts, certain kinds of surfactants, cationic polymers, anionic polymers, or colloidal silly. However, there is a problem that the dependence of temperature and humidity is large and sufficient conductivity cannot be secured at low humidity. Therefore, metal oxides are preferred as materials for the conductive layer. Such metal oxides are undesirable because some of the metal oxides are colored and when the metal oxide is used as the conductive layer material, the entire film is colored. The metal which forms a metal oxide without coloring contains Zn, Ti, Sn, Al, In, Si, Mg, Ba, Mo, W, and V, and it is preferable to use the metal oxide which has these as a main component. Specific examples thereof include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₃ , WO ₃ , V ₂ O ₅ , and composite oxides thereof, and ZnO Particular preference is given to TiO ₂ , and SnO ₂ . As an example including a hetero atom, an additive of Al or In for ZnO, an addition of Sb, Nb, or a halogen element for SnO ₂ , and an addition of Nb or Ta for TiO ₂ are effective. Furthermore, as described in Japanese Patent Publication No. 59-6235, a material in which the above-mentioned metal oxide is attached to different crystalline metal particles or fibrous materials (for example, titanium oxide) may be used. Since the volume resistance value and the surface resistance value are different physical values, they cannot be simply compared. In order to ensure the conductivity of 10-8 (Ωcm-3) at the volume resistance value, the conductive layer may have a surface resistance value of about 10 ^-10 (Ω / square) or less, more preferably 10 ^-8 ( It may have a surface resistance value of (Ω / square) or less. The surface resistance value of the conductive layer is required to be measured as the value when the antistatic layer is disposed as the uppermost layer, and can be measured at the stage during the formation of the laminated film described herein.

(Liquid crystal display)

The cellulose acylate film of this invention, the optical compensation film containing this cellulose acylate film, and the polarizing plate using this optical compensation film can be used for the liquid crystal cell of a various display mode, and a liquid crystal display device. The various display modes proposed so far are TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroelectric Liquid Crystal), OCB (Optical Compensatory Bend), STN (Super Twisted) Nematic), Vertically Aligned (VA), and Hybrid Aligned Nematic (HAN) modes. Among these modes, IPS, OCB, or TN mode can be advantageously used.

The liquid crystal display shown in FIG. 2 has a polarizing film 8, 20, a first retardation region 10, a second retardation region 12, a substrate 13, 17 and a liquid crystal layer sandwiched between these substrates. Has (15). The polarizing film 8 is sandwiched between the protective films 7a and 7b, and the polarizing film is sandwiched between the protective films 19a and 19b.

In the liquid crystal display of Fig. 2, the liquid crystal cell is composed of a liquid crystal layer 15 made of substrates 13 and 17 and a liquid crystal layer 15 sandwiched therebetween. In the IPS type of the liquid crystal cell having no twisted structure, the optimum value of the liquid crystal layer thickness d (μm) and the refractive index anisotropy (Xn), that is, ㅿ n · d, is in the range of 0.2 μm to 0.4 μm in the transmission mode. Within this range, a display device with high contrast and sufficient light emission can be obtained because the white display brightness is high and the black display brightness is low. The substrates 12 and 17 have an alignment film (not shown) formed on their respective surfaces in contact with the liquid crystal layer 15, whereby the liquid crystal molecules are oriented almost parallel to the surface of the substrate. By the rubbing treatment directions 14 and 18 given to the alignment film, the direction of the liquid crystal molecular alignment in the voltage-free state or the low voltage application state can be controlled, respectively. In addition, electrodes (not shown in FIG. 2) are formed on the inner surface of the substrate 13 or 17 to enable voltage application to liquid crystal molecules.

In FIG. 1, the orientation of liquid crystal molecules in one pixel region of the liquid crystal layer 15 is schematically shown. 1 shows the orientation of liquid crystal molecules in an area of a very small area of approximately the same size as one pixel of the liquid crystal layer 15 in the rubbing direction 4 of the alignment film formed on the inner surfaces of the substrates 13 and 17, and the substrate. It is a schematic diagram shown with the electrodes 2, 3 which can apply voltage to liquid crystal molecules formed on the inner surface of (13, 17). When active driving is performed using a nematic liquid crystal having positively induced anisotropy as a field effect liquid crystal, the orientation of liquid crystal molecules in a voltage-free state or a low voltage applied state is 5a and 5b, and at this time, the black state display device Is obtained. When a voltage is applied between the electrodes 2, 3, the liquid crystal molecules change their orientation in the 6a and 6b directions according to the applied voltage. In this condition, a bright state display is usually performed.

Returning to the description of FIG. 2, the transmission axis 9 of the polarizing film 8 and the transmission axis 21 of the polarizing film 20 are arranged to be perpendicular to each other. The slow axis 11 of the first retardation region 10 (the cellulose acylate film of the present invention) is formed by the transmission axis 9 of the polarizing film 8 and the liquid crystal molecules of the liquid crystal layer 15 in the black state display. Parallel to the slow axis direction 16.

In the liquid crystal display shown in Fig. 2, the polarizing film 8 is sandwiched between two protective films 7a and 7b, but the protective film 7b may not be present. In addition, although the polarizing film 20 is sandwiched between two protective films 19a and 19b, the protective film 19a of the side close to the liquid crystal layer 15 may not be provided. In the embodiment shown in FIG. 2, the first retardation region and the second retardation region (rod-like liquid crystal compound layer according to the present invention) are disposed between the liquid crystal cell and the polarizing film on the viewing side based on the position of the liquid crystal cell. It may be arranged, or may be disposed between the liquid crystal cell and the polarizing film located on the back of the display. In each of these configurations according to the mode of practicing the present invention, the second retardation region is located close to the liquid crystal cell.

Another mode for practicing the invention is shown in FIG. 3. In the liquid crystal display shown in FIG. 3, the second retardation region 12 is disposed between the polarizing film 8 and the first retardation region 10. In the liquid crystal display shown in Fig. 3, there may be no protective film 7b or protective film 19a. In the embodiment shown in FIG. 3, the first retardation region 10 has liquid crystal molecules of the liquid crystal layer 15 when the slow axis 11 is displayed in the black state on the transmission axis 9 of the polarizing film 8. It is arranged to be orthogonal to the slow axis direction 16 of. In addition, in the embodiment shown in FIG. 3, the first retardation region and the second retardation region may be disposed between the liquid crystal cell and the polarizing film on the viewing side based on the position of the liquid crystal cell, or The display device may be disposed between polarizing films positioned on the rear surface of the display device. In each of these configurations that differ from the mode of implementation of the present invention, the first retardation region is located closer to the liquid crystal cell.

In addition, in FIG. 3, an embodiment of the display device in the transmissive mode provided with the upper polarizer and the lower polarizer is shown, but the embodiment of the present invention may be a reflective mode display device provided with only one polarizer. In this case, the optical path in the liquid crystal cell is doubled, so that the optimum value of n · d becomes about 1/2 as mentioned above. Further, the liquid crystal cell used in the present invention is not limited to the liquid crystal cell in IPS mode, and any liquid crystal molecules can be oriented substantially parallel to the surfaces of the pair of substrates mentioned above at the time of black state display. Liquid crystal displays can be used as appropriate. Examples of such displays include ferroelectric liquid crystal displays, antiferroelectric liquid crystal displays, and ECB mode liquid crystal displays.

The structure of the liquid crystal display device according to the present invention is not limited to the configuration shown in FIGS. 1 to 3, and may include other members. For example, a color filter may be disposed between the liquid crystal layer and the polarizing film. Moreover, the surface of the protective film of the polarizing film may be antireflected and a hard coating may be provided. In addition, the structural member provided with electroconductivity can also be used. When using a display device as a transmission type, a backlight using a cold cathode or hot cathode fluorescent tube, a light emitting diode, a field emission device, or an electroluminescent device as a light source may be disposed on the back of the display device. In this case, the position of the backlight may be any one of the upper side and the lower side of FIGS. 2 and 3, respectively. Furthermore, a reflective polarizing plate, a diffusion plate, a prism sheet, and an optical waveguide can be disposed between the liquid crystal layer and the backlight. Alternatively, as mentioned above, the liquid crystal display according to the present invention may be reflective. In this case, only one polarizing plate may be arranged on the viewing side, and the reflective film is disposed on the back surface of the liquid crystal cell or on the inner surface of the lower substrate of the liquid crystal cell. Of course, it is also possible to provide the front light using the above-mentioned light source to the liquid crystal cell observation side.

The liquid crystal display device according to the present invention includes an image direct-view display device, an image projection display device, and a light modulation display device. The present invention is particularly effective in the embodiment applied to an active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as a TFT or a MIM. Of course, it is also effective in the embodiment applied to the passive matrix liquid crystal display device called time division drive.

In the OCB mode liquid crystal display, a liquid crystal display using a bend alignment mode liquid crystal cell in which rod-shaped liquid crystal molecules present in an upper region of a liquid crystal cell are arranged in a direction substantially opposite to a direction in which rod-shaped liquid crystal molecules present in a lower region are arranged. Device (the former are arranged symmetrically to the latter). OCB mode liquid crystal cells are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the orientation of the rod-shaped liquid crystal molecules in the upper region of the liquid crystal cell and the orientation of the rod-shaped liquid crystal molecules in the lower region are symmetrical, the bend alignment liquid crystal mode is also referred to as an OCB (Optically Compensatory Bend) liquid crystal mode. Therefore, this liquid crystal mode is also preferable as an OCB liquid crystal mode. The band alignment mode liquid crystal display is advantageous for quick response.

The present invention will now be described in more detail based on the following examples, but these examples should not be construed as limiting the scope of the invention.

[How to measure]

(Retardation)

Re ((lambda)) was measured by injecting light of wavelength (lambda) nm in a normal direction to the film surface by KOBRA 21ADH (made by Oji Scientific Instruments). In addition, the value of Rth (λ) is inclined by + 40 ° with respect to the film normal direction using three retardation values measured in three different directions, that is, the retardation value Re (λ) described above and the in-plane slow axis as the inclination axis. Retardation value measured under the condition of incidence of light of wavelength λnm from the true direction, and Rita measured under the condition of incidence of light of wavelength λnm from the direction inclined at -40 ° to the film normal direction with the in-plane slow axis as the inclination axis. Based on the value of the date, it was calculated by inputting the film thickness and the value 1.48 assumed as the average refractive index. Incidentally, the wavelength λ for the measurement of Re and Rth was set to 550 nm unless otherwise stated.

(Water content)

The moisture content of the sample dimensions (7 mm × 35 mm) was determined using Karl Fisher technique, moisture measuring device, and sample dryer (CA-03 and VA-05, Mitsubishi Chemical Corporation). The moisture content was calculated by dividing the water mass (g) by the mass (g) of the sample.

(Heat shrinkage)

Sample dimensions (30 mm x 120 mm) were placed at 90 ° C and 5% RH for 24 hours and 120 hours, respectively, and 6 mmφ along each edge of each sample using an automatic pin gauge (Shinto Scientific Co., Ltd). Holes were punched at 100 mm intervals. The actual dimension (L1) of the gap was read down to the minimum division scale of 1/1000 mm. Furthermore, each sample was placed for 24 hours under 60 ° C., 95% RH conditions or 90 ° C., 5% RH conditions, and the dimension L2 of each punched gap was measured. And the heat shrinkage rate is determined by the formula {(L1-L2) / L1} × 100.

(Glass transition temperature Tg)

After adjusting the film sample (before stretching treatment) dimensions (5 mm × 30 mm) at 25 ° C. and 60% RH for at least 2 hours, using a viscoelasticity measuring device (Vibron DVA-225, IT Keisoku Seigyo KK) Tg was examined by setting an intergrip distance of 20 mm, a temperature increase rate of 2 deg. C / min, a measurement temperature range of 30 deg. C to 200 deg. When plotting the storage elastic modulus on the logarithmic scale on the vertical axis and the temperature (° C.) on the linear axis on the vertical axis, it can be seen that the storage elastic modulus rapidly decreases when the storage elastic modulus moves from the solid region to the glass transition region. A straight line 1 was drawn along the steep decrease of the solid region and a straight line 2 was drawn along the steep decrease in the glass transition region. The intersection between the straight line 1 and the straight line 2 is the glass transition temperature Tg (dynamic viscoelasticity) because the storage elastic modulus decreases rapidly at the time of temperature rising and the temperature is lowered to the temperature at which the film begins to soften. Obtained as

(Elastic modulus)

After adjusting the film sample dimension (10 mm × 200 mm) for 2 hours under the condition of 20 ° C. and 60% rh, a tensile tester (Strongraph R-2, Toyo Seiki Seisaku-sho, Ltd.). And the elasticity was computed from tensile stress and elongation.

(Photoelastic coefficient)

Tensile stress was applied to the major axis of the film sample dimension (10 mm × 200 mm), and the Re value was measured with an ellipsometer (M150, JASCO Corporation) under this tensile stress. The photoelastic coefficient was calculated from the amount of retardation change by the stress.

(Haze)

The haze of the sample having the size (40 mm x 80 mm) was measured according to JIS K6714 at 25 ° C and 60% RH using a haze meter (HGM-2DP, manufactured by Suga Test Instruments Co., Ltd.).

(Measurement method of hydraulic permeability)

Regarding the method for measuring the hydraulic permeability (moisture permeability), the method is Kobunshi Jikken Koza 4 ( Course 4 in Experiments of High Polymers ) -Kobunshi no Bussei Ⅱ (Physical Properties of High Polymer II) -, pages 285-294 (where the measurement of vapor permeation (weight method, thermometer method, vapor pressure method, and adsorption amount method) is described), Kyoritsu Shuppan Co., Ltd., may be applied. In the following example, it measured at the temperature of 40 degreeC, and the humidity of 90% RH according to JIS-standard JISZ0208 and B conditions.

Example  One

1. Formation of Cellulose Acylate Film

(1) cellulose acylate

As shown in Table 1a, cellulose acylates having different degrees of acyl substitution were prepared. More specifically, carboxylic acid was added as a catalyst other than sulfuric acid (the amount of 7.8 mass parts with respect to 100 mass parts of cellulose), and the acylation reaction was performed at 40 degreeC. Thereafter, the total substitution degree and the 6-position substitution degree were adjusted by adjusting the amount of sulfuric acid catalyst, the amount of water, and the aging time. Aging was carried out at 40 ° C. Furthermore, the low molecular weight component of the cellulose acylate thus prepared was washed with acetone and removed.

(2) dope preparation

A plasticizer (2: 1 mixture of triphenyl phosphate and biphenyldiphenyl phosphate), a retardation expression agent having a structure shown below, and a mixed solvent (dichloromethane and methanol) in each of the cellulose acylates shown in Table 1a. 87:13 parts by mass of) was added by stirring in an amount such that the resulting mixture had a total solid concentration of 19% by mass. The stirring was further continued in the heating state, and the solution was prepared. At the same time, with respect to 100 parts by mass of cellulose acylate, 0.05 parts by mass of fine particles [silicon dioxide (primary particle size: 20 nm, Mohr's hardness: about 7)], ultraviolet absorber B (TINUVIN327, manufactured by Ciba Specialty Chemicals) 0.375 A mass part and 0.75 mass part of ultraviolet absorber C (TINUVIN328, the Ciba Specialty Chemicals make) were thrown, and it stirred, heating. The addition ratio of a plasticizer and a retardation expression agent was shown in Table 2 by mass parts per 100 mass parts of cellulose acylate. From the dope thus prepared, films of F1 to F10 and F14 to F17 were formed in the following manner according to the method described below.

Retardation Expression

While stirring, the plasticizer (2: 1 mixture of triphenyl phosphate and biphenyldiphenyl phosphate), the retardation expression agent having the structure shown above and methyl acetate, acetone, ethanol, and butanol, the resulting mixture was 16.4. It stirred and injected in the quantity which has the total solid concentration of mass%, and the cellulose acylate expanded by this. At the same time, 0.05 parts by mass of fine particles [silicon dioxide (primary particle size: 20 nm, Mohs hardness: about 7)] were respectively used for 100 parts by mass of cellulose acylate, and ethyl citrate (1: 1 of monoethyl citrate and diethyl citrate). Mixture) 0.04 parts by mass. The addition ratio of a plasticizer and a retardation expression agent was shown in Table 1 by mass parts per 100 mass parts of cellulose acylate. The thus expanded solution was cooled to -70 ° C, heated to 40 ° C, and dissolved. The dope thus obtained was filtered, flash concentration was further performed at 120 ° C, and the solid content concentration of the dope was adjusted to about 21%. From the dope prepared in this way, films F11-F13 were manufactured by the following method.

(Flow casting)

Each dope was flow casted in a band casting machine. Each film thus prepared was peeled from the band when the amount of residual solvent was reduced in the range of 25 to 35% by mass, and stretched in the width direction using a tenter at an elongation of 15% to 23% (see Table 2) to give cellulose. An acylate film was prepared. In the tenter, the film was stretched in the width direction while being exposed to warm air and dried, and then contracted by about 5%. Thereafter, tenter conveyance was changed to roll conveyance, the drying was further performed, and it knurled and wound up. Elongation was calculated from the film width measured at the inlet of the tenter and the film width measured at the outlet of the tenter, and is shown in Table 1b. For each of the cellulose acylate films (optical compensation films) thus prepared, the values of Re retardation and Rth retardation were measured at a wavelength of 550 nm at 25 ° C. and 60% RH. Furthermore, each film was conditioned at 25 ° C., 10% RH, or 80% RH for at least 2 hours, sandwiched through silicon between the two glasses, and the Re and Rth retardation values of each film were kept in a sealed state. Measured. Re-retardation change amount of each cellulose acylate film due to humidity change of 80% RH to 10% RH, Re (10% RH)-Re (80% RH), and humidity of 80% RH to 10% RH The amount of change in Rth retardation caused by the change, Rth (10% RH)-Rth (80% RH), is shown in Table 2 as symbols? Re and? Rth, respectively.

Total substitution is the sum of the 2-, 3-, and 6-position substitutions, and is the same as acetyl substitution plus propionyl substitution.

Furthermore, the measurements obtained by measuring the water content after moisture conditioning at the glass transition temperature (Tg), 25 ° C. and 80% RH, and the water transmittance under the conditions of 60 ° C., 95% RH, and 24 hours on the films respectively prepared The calculated values are shown in Table 2. The haze of these films was all in the range of 0.1 to 0.9, the average diameter of the secondary particles made of mat was 1.0 μm, the tensile modulus was 4 GPa or more, and the mass change when placed for 48 hours under the conditions of 80 ° C. and 90% RH. Was 0% to 3%. Moreover, the dimensional change in 24 hours under 60 degreeC and 95% RH conditions, and the dimensional change in 24 hours under 90 degreeC and 5% RH conditions were 0%-4.5%. Moreover, the photoelastic coefficient of all the sample films was 50 × 10 ⁻¹³ cm ² / dyne or less.

Other films were formed in the same manner as the optical film F13 described in Table 2, except that the dry thickness was changed to 143 mu m and 176 mu m, respectively, and the dry thickness of F13 was 1.3 and 1.6 times. From these films, it was confirmed that the Re and Rth values which increased at an approximate ratio with respect to thickness and moisture permeability were almost inversely proportional to the thickness. The humidity dependences of Re and Rth, i.e., Re and Rth, the glass transition temperature (Tg), and the water content, are each independent of thickness, and the film has the same value for each of its factors.

Each cellulose acylate film (F1 to F17) has 10 cc of 1.0 N potassium hydroxide solution (solvent: water / isopropyl alcohol / propylene glycol = 69.2 parts by mass / 15 parts by mass / 15.8 parts by mass) on the band contacting side. / m ² coating and hold on each film for 30 seconds at a temperature of about 40 ° C. Thereafter, the solution was scraped off, the film surface was washed with pure water, and water dope was removed with an air knife. Then, it dried for 15 second at 100 degreeC. The contact angle of pure water with respect to the alkali treatment surface was 42 degrees.

(Formation of Orientation Film)

A commercially available composition (JALS-204R, manufactured by JSR) for a vertically oriented film was diluted with methyl ethyl ketone in a ratio of 1: 1, and a cellulose film (F1 to F17) in the range of 2.4 m1 / m ^{2 with} a wire bar coater. Immediately after coating on each, it dried for 120 second by 120 degreeC at warm air.

Next, 3.8 g of the rod-like liquid crystalline compound shown below, 0.06 g of a photopolymerization initiator (Irgacure907, manufactured by Ciba Geigy AG), 0.02 g of a photosensitizer (KAYACURE DETX, manufactured by Nippon Kayaku), and the air interface side vertical described below A solution was prepared by dissolving 0.002 g of the aligning agent in 9.2 g of methyl ethyl ketone. And the solution was apply | coated to each film in which the orientation film was formed using each wire bar which has the counter demonstrated below on the orientation film surface side. To each film to which the solution was applied, a metal frame was bonded and heated in a temperature controlled chamber at 100 ° C. for 2 minutes to orient the rod-like liquid crystal compound. Thereafter, UV irradiation is performed for 20 seconds with a 120 W / cm high pressure mercury vapor lamp at 80 ° C. to form crosslinks between the rod-like liquid crystalline molecules. Thereafter, each film was cooled to room temperature. Thus, the optically anisotropic film was produced.

The viscosity of each optically anisotropic film measured at a film surface temperature of 90 ° C. was 495 cp. This viscosity value was the result of having measured the liquid crystal layer (solvent removed) which has the same composition as an optically anisotropic layer with the heating type rotational viscometer.

Rod shape Liquid crystalline  compound

Air Interface Side Sujin Alignment agent

Exemplary compound (II-4) described in Japanese Patent No. 2003-119959

The dependence of Re on the light incidence angle of each film thus prepared is determined by an automatic birefringence meter (KOBRA-21ADH, Oji Scientific Instruments, measuring wavelength: 550 nm), and each subtracted contribution of a predetermined support The optical properties of the individual optically anisotropic layers only were calculated. As a result, KH-01 and KH-H1 each have a Re value of 0 nm, an Rth value of -225 nm, a KH-02 value of a Re value of 0 nm, an Rth value of -295 nm, and a KH-03 value of Re. It was 0 nm, Rth value was -180 nm, KH-04 confirmed that Re value was 0 nm, Rth value was -260 nm, and all rod-like liquid crystalline compounds were orientated perpendicularly in all the films.

<Production of Polarizing Plate Protective Film 1>

Next, the composition was put in a tank, stirred while heating to dissolve the component, and cellulose acetate solution A was prepared.

Cellulose Acetate Solution A Composition:

100 parts by mass of cellulose acetate having a degree of substitution of 2.86

Triphenyl phosphate (plasticizer) 7.3 parts by mass

Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by mass

Methylene chloride (first solvent) 300 parts by mass

54 parts by mass of methanol (second solvent)

11 parts by mass of 1-butanol

The following composition was put into another mixing tank, it stirred while heating, the component was dissolved, and the additive solution B-1 was prepared.

<Additive solution B-1 composition>

80 parts by mass of methylene chloride

20 parts by mass of methanol

40 parts by mass of optically anisotropic reducing agent

40 mass parts of additive solution B-1 were added to 477 mass parts of cellulose acetate solutions A, and it fully stirred, and dope was prepared. The dope was cast on a drum cooled at 0 ° C. from the casting die. The film produced in the state in which the solvent content reaches 70 mass% was peeled off from the drum, and the solvent content in the state where both film edges were fixed in the width direction with a pin tenter (described in JP-A-4-1009). When it was 3 mass%-5 mass%, it dried, maintaining the space | interval which the elongation of a horizontal direction (direction perpendicular | vertical to a machine direction) becomes 3%. Then, it conveyed between the rolls installed in the heat processing apparatus, dried the film further, and manufactured the polarizing plate protective film 1 which has a thickness of 80 micrometers.

The optical incident angle dependence of Re of the film thus produced was measured using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instrument), and the optical properties of the film were calculated. This calculation confirmed that Re was 1 nm and Rth was 6 nm.

(Manufacture of Polarizer)

The optical compensation films (KH-01 to KH-04, and KH-H1) were laminated | stacked on the polarizing film in the state which stuck the polarizing film to the side of the transparent support body using the polyvinyl alcohol-type adhesive agent. In addition, after a saponification process was performed to the antireflection film (Fiji Film CV Clear View UA, Fuji Photo Film Co., Ltd. product), it laminated | stacked on the side opposite to a polarizing film using a polyvinyl alcohol-type adhesive agent.

After a saponification process was performed to the commercially available triacetyl cellulose film (TD-80U, Fuji Photo Film Co., Ltd. product) of thickness 80micrometer, it laminated | stacked on the side opposite to a polarizing film using a polyvinyl alcohol-type adhesive agent.

The polarizing film, the transparent support body, and the commercially available triacetyl cellulose film were arrange | positioned so that it might become parallel with the longitudinal direction of a polarizing film, the longitudinal direction of a transparent support body, and the longitudinal direction of a commercially available triacetyl cellulose film. In this way, a polarizer (polarizing plate 1) having optical compensation was produced.

In addition, using a polyvinyl alcohol adhesive, a saponified polarizing plate protective film 1 is laminated on one side of the polarizing film, and a commercially available triacetyl cellulose film (TD-80U, Fuji Photo Film Co) having a thickness of 80 µm previously saponified. ., Ltd.) was laminated on the other side of the polarizing film using a polyvinyl alcohol adhesive.

The polarizing film, the transparent support body, and the commercially available triacetyl cellulose film were arrange | positioned so that it might become parallel with the longitudinal direction of a polarizing film, the longitudinal direction of a transparent support body, and the longitudinal direction of a commercially available triacetyl cellulose film. In this way, a polarizer (polarizing plate 2) having optical compensation was produced.

Using a spectrophotometer (UV3100PC), on the polarizing plate prepared by combining the cellulose acylate film prepared in the example and the polarizer so that the film is positioned inside the polarizer, the wavelength region under conditions of 25 ° C. and 60% RH 380 Single plate transmittance (TT), parallel transmittance (PT), and orthogonal transmittance (CT) of nm to 780 nm were measured. From these measurements, the average value and polarization degree P of the wavelength range 400 nm-700 nm were determined. As a result, it was found that TT is 40.8 to 44.7, PT is 34 to 38.8, CT is 1.0 or less, and P is 99.98 to 99.99. In addition, the orthogonal transmittances CT 380, CT 410, and CT 800 at wavelengths 330 nm, 410 nm, and 700 nm were 1.0 or less, 0.5 or less, and 0.3 or less, respectively. Furthermore, in the durability test of 500 hours under the condition of 60 ° C. and 95% RH, all polarizing plates were in the range of −0.1 ≦ ㅿ CT ≦ 0.2, −2.0 ≦ ㅿ P ≦ 0, while 60 ° C, 90% In the durability test at RH, it was in the range -0.05 ≦ ㅿ CT ≦ 0.15, −1.5 ≦ ㅿ P ≦ 0.

One portion of each polarizer (1,2; polarizer integrated with the optical compensation film without the functional film shown in FIG. 2) is stored in a moisture proof bag, and the other part is subjected to moisture control at 25 ° C., 60% RH for 2 hours. And then stored in moisture-proof bags. The moisture proof bag was found to be a package consisting of a stack of polyethylene, terephthalate, aluminum, and polyethylene, and its water vapor transmission rate was 0.01 mg / m ² (24 hours).

<Production of IPS Mode Liquid Crystal Cell>

As shown in Fig. 1, electrodes (2 and 3 in Fig. 1) are disposed on one glass substrate so as to maintain a distance of 20 mu m between adjacent electrodes. A polyimide film is arrange | positioned on it, a rubbing process is performed, and an oriented film is prepared. The rubbing treatment was performed in the direction 4 as shown in FIG. Another orientation film was prepared by providing a polyimide film to one side of the other sheet of a glass substrate, and performing a rubbing process. The two glass substrates were laminated so that the orientation films faced each other, the gap d between the two glass substrates was maintained at 3.9 µm, and the rubbing directions thereof were parallel to each other. Its interior was sealed with a nematic liquid crystal composition having a refractive index anisotropy of 0.0769 and a dielectric anisotropy of +4.5. The d · ㅿ n value of the liquid crystal layer was 300 nm.

(Manufacture of liquid crystal display device)

On one side of the IPS mode liquid crystal cell, the slow axis of the cellulose acylate film is parallel to the rubbing direction of the liquid crystal cell (in other words, the slow axis of the cellulose acylate film in the black state liquid crystal cell is The polarizing plate 1 was laminated | stacked so that it might become parallel, and also the rod-like compound layer was located in the side of the liquid crystal cell.

Subsequently, on the other side of the IPS mode liquid crystal cell (1 in FIG. 1), the polarizing plate 2 is laminated so that the side of the polarizing plate protective film 1 faces the liquid crystal cell side, and in addition, the polarizing plates 1, 2 ) Is in a cross nicol arrangement, whereby a liquid crystal display device is manufactured. The light leakage of the liquid crystal display thus manufactured was examined. In all cases using films (KH-01 to 04 and KH-H1), light leakage of 0.1% or less was found when viewed in a direction tilted to the left at an angle of 60 °.

On the other hand, the light leakage when the optical compensation film was not used was 0.6%.

Furthermore, after one week storage at 25 ° C, 80% RH and 25 ° C, 10% RH, the liquid crystal display using KH-01 and the liquid crystal display using KH-H1 were examined for viewing angle characteristics, respectively.

(Evaluation of Liquid Crystal Display)

A 55 Hz square wave voltage was applied to the liquid crystal cell. In normally black mode, the black status indicator was set at 0V and the white status indicator was set at 7V. The transmittance (white state display device / black state display device) was taken as the contrast ratio, and the viewing angle was measured in eight stages from the black state display device L1 to the white state display device L8. In addition, the front contrast (CR: brightness of the white state display device / brightness of the black state display device) was also determined.

The obtained results are shown in Table 1c.

Example  2

1. Formation of Cellulose Acylate Film

(1) cellulose acylate

As shown in Table 2a, cellulose acylates having different degrees of acyl substitution were prepared. More specifically, sulfuric acid was added as a catalyst (amount of 7.8 mass parts with respect to 100 mass parts of cellulose) as a catalyst, and the acylation reaction was performed at 40 degreeC. Thereafter, the total substitution degree and the 6-position substitution degree were adjusted by adjusting the amount of sulfuric acid catalyst, the amount of water, and the aging time. Aging was carried out at 40 ° C. Furthermore, the low molecular weight component of the cellulose acylate thus prepared was washed with acetone and removed.

(2) dope preparation

A plasticizer (2: 1 mixture of triphenyl phosphate and biphenyldiphenyl phosphate), a retardation expression agent having the structure shown below, or a mixture of dichloromethane / methanol in each of the cellulose acylates shown in Table 2a (87 : 13 mass) was added while stirring in an amount in which the resulting mixture had a total solid concentration of 19 mass%. The stirring was further continued in the heating state, and the solution was prepared. At the same time, 0.05 parts by mass of fine particles [silicon dioxide (primary particle size: 20 nm, Mohs hardness: about 7)] with respect to 100 parts by mass of cellulose acylate, 0.375 parts by mass of ultraviolet absorber B (TINUVIN327, manufactured by Ciba Specialty Chemicals), ultraviolet 0.75 mass part of absorbent C (TINUVIN328, the product made by Ciba Specialty Chemicals) was thrown in, and it stirred, heating. The addition ratio of a plasticizer and a retardation expression agent was shown in Table 1 by mass parts per 100 mass parts of cellulose acylate. From the dope thus prepared, films of F1 to F10 and F14 to F17 were formed in the following manner according to the method described below.

Retardation Expression

While stirring, a plasticizer (2: 1 mixture of triphenyl phosphate and biphenyldiphenyl phosphate), a retardation expression agent having the structure shown above, and 81: 81: 8 of methyl acetate, acetone, ethanol, and butanol The: 4 mass mixture was further fed to the cellulose acylate CA3 shown in Table 1 in an amount in which the resulting mixture had a total solid concentration of 16.4 mass%, thereby expanding the cellulose acylate. At the same time, 0.05 parts by mass of fine particles [silicon dioxide (primary particle size: 20 nm, Mohs hardness: about 7)] with respect to 100 parts by mass of cellulose acylate, a mixture of ethyl citrate (monoethyl citrate and diethyl citrate 1: 1) ) 0.04 parts by mass was added. The addition ratio of a plasticizer and a retardation expression agent was shown in Table 1 by mass parts per 100 mass parts of cellulose acylate. The thus expanded solution was cooled to -70 ° C, heated to 40 ° C, and dissolved. The dope thus obtained was filtered, flash concentration was further performed at 120 ° C, and the solid content concentration of the dope was adjusted to about 21%. From the dope prepared in this way, the films F11-F13 were manufactured by the following method.

(Flow casting)

Each dope was cast in a band casting machine. Each film thus prepared was peeled off from the band when the amount of residual solvent was reduced in the range of 25% by mass to 35% by mass, and stretched in the width direction using a tenter at an elongation of 15% to 23% (see Table 2). And cellulose acylate film were produced. In the tenter, the film was stretched in the width direction while being exposed to warm air and dried, and then contracted by about 5%. Thereafter, tenter conveyance was changed to roll conveyance, the drying was further performed, and it knurled and wound up. Elongation was calculated from the film width measured at the inlet of the tenter and the film width measured at the outlet of the tenter, and is shown in Table 2b. The cellulose acylate film (optical compensation film) thus produced was measured for Re retardation and Rth retardation at a wavelength of 550 nm at 25 ° C. and 60% RH. Furthermore, each film was conditioned at 25 ° C., 10% RH, or 80% RH for at least 2 hours, sandwiched through silicon between the two glasses, and the Re and Rth retardation values of each film were kept in a sealed state. Measured. Change in Re-retardation by each cellulose acylate film due to humidity change from 80% RH to 10% RH, Re (10% RH)-Re (80% RH), and humidity from 80% RH to 10% RH The amount of change in Rth retardation, Rth (10% RH)-Rth (80% RH) due to the change, is shown in Table 2b as the symbols? Re and? Rth, respectively.

Total substitution degree is the sum of 2-, 3-, and 6-position substitution degree, and is the same as ethethyl substitution degree plus propionyl substitution degree.

Furthermore, the measured and obtained moisture content was measured by measuring the glass transition temperature (Tg), the water content after moisture conditioning at 25 ° C., 80% RH, and the water permeability under conditions of 60 ° C., 95% RH, and 24 hours on each of the prepared films. The values are also shown in Table 2. The haze of these films was all in the range of 0.1 to 0.9, the average diameter of the secondary particles made of mat was 1.0 μm, the tensile modulus was 4 GPa or more, and the mass change when placed for 48 hours under the conditions of 80 ° C. and 90% RH. Was 0% to 3%. Moreover, the dimensional change in 24 hours under 60 degreeC and 95% RH conditions, and the dimensional change in 24 hours under 90 degreeC and 5% RH conditions were 0%-4.5%. Moreover, the photoelastic coefficient of all the sample films was 50 × 10 ⁻¹³ cm ² / dyne or less.

Other films were produced in the same manner as the optical film (F13) described in Table 2, except that the dry thicknesses of F13 were 1.3 times and 1.6 times by changing the dry thickness to 143 mu m and 176 mu m, respectively. From these films, it was confirmed that the Re and Rth values which increased at an approximate ratio with respect to thickness and moisture permeability were almost inversely proportional to the thickness. The humidity dependences of Re and Rth, i.e., Re and Rth, the glass transition temperature (Tg), and the water content, are each independent of thickness, and the film has the same value for each of its factors.

Each cellulose acylate film (F1 to F17) has 10 cc of 1.0 N potassium hydroxide solution (solvent: water / isopropyl alcohol / propylene glycol = 69.2 parts by mass / 15 parts by mass / 15.8 parts by mass) on the band contacting side. / m ² coating and hold on each film for 30 seconds at a temperature of about 40 ° C. Thereafter, the solution was scraped off, the film surface was washed with pure water, and water dope was removed with an air knife. Then, it dried for 15 second at 100 degreeC. The contact angle of pure water with respect to the alkali treatment surface was 42 degrees.

(Formation of Orientation Film)

To each of the alkali treated surfaces of the cellulose acylate films (F1 to F17), a coating liquid for forming an oriented film having the compound described below was applied in an amount of 2.8 ml / m ² using a # 16 wire bar coater. Thereafter, the applied solution was dried for 60 seconds with 60 DEG C warm air, and then further dried for 90 seconds with 90 DEG C warm air to form an oriented film.

Composition of Coating Solution for Orientation Film

10 parts by mass of the modified polyvinyl alcohol below

371 parts by mass of water

119 parts by mass of methanol

0.5 part by mass of glutaraldehyde (crosslinking agent)

0.35 parts by mass of citric acid ester (AS3, Sankyo Chemical Co., Ltd)

Modified polyvinyl Alcohol

(Rubbing treatment)

While each transparent support having the alignment film formed by the above method is transported at a speed of 20 m / min, a rubbing roll is carried out at a 40 ° angle to the longitudinal direction and arranged to rotate at 650 rpm (diameter At 300 mm) to rub the surface of the alignment film formed on the transparent support. Here, the connection length between the rubbing roll and the transparent support was set to 18 mm.

(Formation of optically anisotropic layer)

102 Kg of methyl ethyl ketone to 41.01 Kg of the discotic liquid crystalline compound described below, 4.06 Kg of ethylene oxide modified triethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Industry Ltd.), 0.35 Kg of cellulose To acetate butyrate (CAB 531-1M, manufactured by Eastman Chemical Company), 1.35 Kg of photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy AG), and 0.45 Kg of photosensitizer (manufactured by KAYACURE DETX, Nippon Kayaku Co., Ltd.) Dissolved. A solution obtained was added to a 0.1 Kg copolymer-containing fluorinated aliphatic group (Megafac F780, manufactured by Dainippon Ink and Chemicals, Incorporated). The coating liquid thus prepared was continuously applied to the surface of the oriented film on each transparent support carried at a speed of 20 m / min by a # 3.2 wire bar rotating means at 391 revs in the same direction as the film feeding direction.

Discotic Liquid crystalline  compound

After the solution was removed by drying with continuous heating at room temperature to 100 ° C, each film was fed to a 130 ° C dry zone. In the dry zone, each film is heated for about 90 seconds under conditions in which the surface of the optically anisotropic discotic layer is blown to adjust the film surface viscosity to 2.5 m / sec, thereby aligning molecules of the discotic liquid crystal compound. I was. Next, the resultant film was supplied to an 80 ° C. dry region, and the surface temperature was about 100 ° C., followed by 600 by an ultraviolet irradiation device (ultraviolet lamp having an output of 160 W / cm and an emission length of 1.6 m). Ultraviolet irradiation is carried out for 4 seconds by illumination of mW, which results in a crosslinking reaction for fixing the orientation state of the discotic liquid crystal compound molecules. Thereafter, each was formed into a roll by cooling the film to room temperature and winding it around a cylinder. Thus, roll forming optical compensation films (KH-01 to 17) were formed.

The viscosity of each optically anisotropic film measured at film surface temperature of 127 ° C. was 695 cps. This viscosity value was the result of having measured the liquid crystal layer (solvent removed) which has the same composition as an optically anisotropic layer with the heating type rotational viscometer.

A part of the roll forming optical compensation film formed in this way was cut | disconnected, the sample was prepared, and the optical characteristic of these samples was specified. When measured at a wavelength of 546 nm, the Re retardation value of the optically anisotropic layer was 380 nm. It was found that the angle (inclined angle) in which the disk plane of the discotic liquid crystalline compound in the optically anisotropic layer was formed on the support surface changed continuously in the depth direction of the layer, and the average tilt angle was 28 °. Moreover, only the optically anisotropic layer was peeled off each sample. When the average direction of the molecular symmetry axis of the optically anisotropic layer was determined, it was found that the average direction forms an angle of 45 ° with respect to the longitudinal direction of the optical compensation film.

(Manufacture of Polarizer)

The optical compensation film (KH-06, KH-08, and KH-17) was laminated | stacked on the polarizing film in the state which stuck the polarizing film to the side of the transparent support body using the polyvinyl alcohol-type adhesive agent. In addition, after saponifying the commercially available 80 micrometer-thick triacetyl cellulose film (TD-80U, Fuji Photo Film Co., Ltd. product), it laminated | stacked on the side opposite to a polarizing film using a polyvinyl alcohol-type adhesive agent.

The polarizing film, the transparent support body, and the commercially available triacetyl cellulose film were arrange | positioned so that it might become parallel with the longitudinal direction of a polarizing film, the longitudinal direction of a transparent support body, and the longitudinal direction of a commercially available triacetyl cellulose film. In this way, polarizers having different optical compensation films were produced.

Moreover, each optical compensation film was laminated | stacked on one side of the polarizing film in the state which stuck the polarizing film to the side of the said transparent support body using the polyvinyl alcohol-type adhesive agent. In addition, the antireflection film (Fiji Film CV Clear View UA, manufactured by Fuji Photo Film Co., Ltd.) was saponified, and then laminated on the other side of the polarizing film using a polyvinyl alcohol-based adhesive.

The polarizing film, the transparent support body, and the commercially available triacetyl cellulose film were arrange | positioned so that it might become parallel with the longitudinal direction of a polarizing film, the longitudinal direction of a transparent support body, and the longitudinal direction of a commercially available triacetyl cellulose film. In this manner, a polarizer having an antireflection film in addition to the optical compensation film was produced.

Using a spectrophotometer (UV3100PC), on the polarizing plate prepared by combining the cellulose acylate film prepared in Example and the polarizer so that the film is located inside the polarizer, the wavelength region under the conditions of 25 ° C. and 60% RH 380 nm Single plate transmittance (TT), parallel transmittance (PT), and orthogonal transmittance (CT) of 780 nm were measured. From these measurements, the average value and polarization degree P of the wavelength range 400 nm-700 nm were determined. As a result, it was found that TT is 40.8 to 44.7, PT is 34 to 38.8, CT is 1.0 or less and P is 99.98 to 99.99. In addition, the orthogonal transmittances CT 380, CT 410, and CT 800 at wavelengths 330 nm, 410 nm, and 700 nm were 1.0 or less, 0.5 or less, and 0.3 or less, respectively. Furthermore, in the durability test of 500 hours under the condition of 60 ° C. and 95% RH, all polarizing plates were in the range of −0.1 ≦ ㅿ CT ≦ 0.2, −2.0 ≦ ㅿ P ≦ 0, while 60 ° C, 90% In the durability test at RH, it was in the range -0.05 ≦ ㅿ CT ≦ 0.15, −1.5 ≦ ㅿ P ≦ 0.

One part of each polarizing plate (A1 to A17) was stored in a moisture proof bag, and the other part was kept in a moisture proof bag after moisture control at 25 degreeC and 60% RH for 2 hours. The moisture proof bag was found to be a package consisting of a stack of polyethylene, terephthalate, aluminum, and polyethylene, and its water vapor transmission rate was 0.01 mg / m ² (24 hours).

(Manufacture of Bend Orientation Liquid Crystal Cell)

On the glass substrate which has an ITO electrode, the polyimide film was arrange | positioned, the rubbing process was performed, and the orientation film was prepared. Two glass substrates thus produced were laminated so that the orientation films faced each other, their rubbing directions were parallel, and the cell gap d was set at 4.5 µm. A liquid crystal compound (ZLI1132, manufactured by Merck Ltd., Japan) having a n of 0.1396 was injected into the cell gap, whereby a band-oriented liquid crystal cell was produced. The liquid crystal cell was measured 20 inches diagonally.

On the bend alignment cell produced, a polarizer (one) having one of the optical compensation films and a polarizer having both one of the optical compensation films and the antireflection film were sandwiched so that the cell was sandwiched between the polarizers. Here, the polarizer having both the optical compensation film and the antireflection film is located on the viewing side. The optically anisotropic layer of the polarizer facing a cell substrate, the optically anisotropic layer facing a liquid crystal cell, and the liquid crystal cell were arrange | positioned so that the rubbing direction might mutually be parallel.

(Evaluation of Liquid Crystal Display)

A 55 Hz square wave voltage was applied to the liquid crystal cell. The white status indicator was set at 2V and the black status indicator was set at 5V. The transmittance was taken as the contrast ratio (white state display device / black state display device), and the viewing angle was measured in eight stages, the black state display device L1 to the white state display device L8. In addition, the front contrast (CR: brightness of the white state display device / brightness of the black state display device) was also determined.

Furthermore, after storage for 1 week under 20 ° C, 80% RH and 20 ° C and 10% RH, the liquid crystal display was inspected for viewing angle characteristics.

The obtained results are shown in Table 2c.

Those skilled in the art will appreciate that various modifications and changes can be made to the described embodiments of the invention without departing from the spirit or scope of the invention. Accordingly, it is intended that the present invention cover all modifications and variations of this invention provided they are consistent with the scope of the appended claims and their equivalents.

The present invention was filed on March 22, 2005, and claims foreign priority based on Japanese Patent Application Nos. 2005-81401 and 2005-82211, the contents of which are incorporated herein by reference.

Claims (11)

Cellulose acylate film; An optical compensation film comprising an optically anisotropic layer containing a liquid crystalline compound, Wherein the cellulose film comprises cellulose with glucose units, the hydroxyl groups of the glucose units are substituted with acyl groups having two or more carbon atoms, and the cellulose acylate film satisfies the relationship (I) and (II): (I): 2.0 ≤ DS2 + DS3 + DS6 ≤ 3.0 (II): DS6 / (DS2 + DS3 + DS6) ≥ 0.315 DS2 means the degree of substitution of the hydroxyl group at the 2-position of the glucose unit with the acyl group, DS3 means the degree of substitution of the hydroxyl group at the 3-position of the glucose unit with the acyl group, and DS6 is And a degree of substitution of said hydroxyl group into said acyl group at the 6-position of said glucose unit. The method of claim 1, The cellulose acylate film comprises a retardation expression agent comprising one of a rod-shaped compound and a discotic compound. The method of claim 1, The difference between the retardation value Re (550) at 25 ° C and 10% RH and the retardation value Re (550) at 25 ° C and 80% RH, ㅿ Re (Re10% RH-Re80% RH) is 12 nm or less And the difference between the retardation value Rth (550) at 25 ° C and 10% RH and the retardation value Rth (550) at 25 ° C and 80% RH, ㅿ Rth (Rth10% RH-Rth80% RH) 32 nm or less, Re (λ) is an in-plane retardation expressed in nm units at a wavelength of λ nm, and Rth (λ) is a thickness direction retardation expressed in nm units at a wavelength of λ nm. The method of claim 1, The liquid crystal compound is a discotic liquid crystal compound, optical compensation film. The method of claim 1, The liquid crystal compound is an optical compensation film, which is a rod-like liquid crystal compound. The method of claim 5, The cellulose acylate film has a Re (550) value of 20 nm to 150 nm, an Rth (550) / Re (550) ratio of 1.5 to 7, and the optically anisotropic layer has a Re (550) of 0 nm to 10 nm. Value and an Rth (550) value from -80 nm to -400 nm, Re (λ) is an in-plane retardation expressed in nm at a wavelength of λ nm, and Rth (λ) is expressed in nm at a wavelength of λ nm. Optical compensation film which is thickness direction retardation made. Cellulose acylate film; An optical compensation film comprising an optically anisotropic layer containing a liquid crystalline compound, Wherein the cellulose film comprises cellulose with glucose units, the hydroxyl groups of the glucose units are substituted with acyl groups having two or more carbon atoms, and the cellulose acylate film satisfies the relationship (I) and (II): (I): 2.0 ≤ DS2 + DS3 + DS6 ≤ 3.0 (II): DS6 / (DS2 + DS3 + DS6) ≥ 0.315 DS2 means the degree of substitution of the hydroxyl group at the 2-position of the glucose unit with the acyl group, DS3 means the degree of substitution of the hydroxyl group at the 3-position of the glucose unit with the acyl group, and DS6 is And a degree of substitution of said hydroxyl group into said acyl group at the 6-position of said glucose unit. Polarizer; And The polarizing plate containing the optical compensation film in any one of Claims 1-7. Liquid crystal cell; And The liquid crystal display device containing the optical compensation film in any one of Claims 1-7. The method of claim 9, And the liquid crystal cell is in IPS mode. The method of claim 9, Wherein said liquid crystal cell is in OCB mode.

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